I need a "Iridescent Wal-Mart"

[Persephone]

I'm from the US, Blonde, and finishing up my BS in biotechnology with minors in soc and microbio.
Today at the local fish stop i was ordering some inert sand substrate for my 30 gal.and when asked my number i blanked out for a moment and the immediate reply by the salesman was "Well i guess you are a real blonde"

All prejudices aside: How far are you willing to travel and/or dish out to order one of these online?
You should take into acount if you do find one online shipping will most likley be somewhere around 50 usd for overnight+shipping supplies.

As far as wal-mart is concerned i have never walked into a well kept wal-mart fish section so i'd be pretty wary looking there if i were you.

While i agree that you have the right to stock your tank with whatever you wish you really should take into account the plethora of information available here. With the understanding you would like large fish in your tank i do believe there are species that will grow to maximums of say 12/13" for your 100 gal that you could at the least look through (and may even like better tbh) especially given you are looking to order online and pay hefty shipping.

[Moontanman]

Barbie, one of three things has happened here. Either you didn't read the posts very closely, or you didn't understand the posts or thirdly you automatically assume anyone who disagrees with you is wrong. In this discussion I find myself on the side I once considered wrong but because of my personal experience and observations I have started to question what I once thought of as a law of nature. At one time if you had told me that a fish could somehow adjust it's growth to fit the container it was kept in I would have said you weren't playing with a full deck. But now after having seen an iridescent shark cease to grow even though it was in a tank more than big enough for it to have grown and hearing about some peoples experience with many other fishes I have to admit that fish don't always grow to their maximum size. This could be because of some underlying genetic cause I am unaware of that occasionally produces iridescent sharks that are much smaller than normal, I say iridescent sharks because the underlying factor in other fish is plainly not the same in say goldfish or sunfish as it in iridescent sharks. I think it goes deeper than simply stunting a fish when it is young. Since this occurs in the wild I am leaning towards a natural factor that causes fish to limit their size when resources are slim. I have absolutely no data to back this up yet but I have been keeping fish for more than 40 years and I have many friends that have been keeping them far longer than I. Maybe with a little bit of luck we should be able to get together some experienced minds and get some theories together about this phenomenon.

Michael Hissom
Captive Environments, aquaculture

I think the point everyone was trying to make here is that it's in the best interests of the fish to not stunt them in a too small glass box. If you're going to do it anyway and don't want to take advice from people with extensive knowledge on the subject, that's just peachy too, but why waste everyone's time arguing about it? It's like saying my 80 pound dog could have been kept at 35 pounds if I'd just left it in it's crate all the time. You can do it, and keep it alive, but the quality of life is missing. That's not what I am shooting for in my own personal aquariums, but maybe I'm missing something here, who knows.

While I realize you were having issues with the rules link, now that your profile is updated, is there really any need for the negativity about the people on the board? They've simply tried to help, although they haven't had the answers you wanted to hear. That doesn't make them any less intelligent, IMO. It does reflect badly in ways that make me cringe, being a female from the US though. I guess at least I'm not blonde. Think that's the difference?

Seriously though, the people here on this board are my favorite of all the boards I routinely post on. Please step back from the situation and reread the posts everyone has made. I think you'll see they're recommending the healthiest solutions to your problem for you long term.

Barbie

[Bas Pels]

But now after having seen an iridescent shark cease to grow even though it was in a tank more than big enough for it to have grown and hearing about some peoples experience with many other fishes I have to admit that fish don't always grow to their maximum size. This could be because of some underlying genetic cause I am unaware of that occasionally produces iridescent sharks that are much smaller than normal, I say iridescent sharks because the underlying factor in other fish is plainly not the same in say goldfish or sunfish as it in iridescent sharks.

Reading this twice, or more, I think you basically say this:
a some Pangasius just stop growing, even in the best circumstances
b you do not try to defend stunting (good)
c you accept the Pangasius problem might be unrelated to similar questions in other fishes
d genetics could very well be involved

if I than read above that Pangasius is bred commercially, to be eaten, my explanation might look like:

Commercially breeding animals invariably leads to inbreding, and inbreeding will - in a few or more generations - result in gentic defects wich hamper fish growth. further, commercially breeding fish means large groupes, which can have a fwew individuals not getting what they need.

If we further know the big ones are eaten, and the small ones are shipt, I think perhaps quite a lot of Pangasius with genetic defects, or early stunted fishes, are offered here - in fact, perhaps all of them will fall in one of these groupes.

I know, reasoning is dangerous, but should we not conclude that Pangasius offered for aquarium keeping will most likely not reach the normal size?

Bas

[MatsP]

Can I just say that Bas makes a good argument, but one of the assumptions used in that argument is something that I'm only guessing: The fish selected for the aquarium trade is selected "small" fingerlings (roughly finger-sized juveniles) - which is something that would make sense - whether genetically or otherwise these fish are prone to growing to small sizes, they may well be selected based on the fact that they are small at around 3" (which is the size you often see in the shops), and they may be selected out of a bigger group of fish, most of which are larger [for example by using a coarse net, fish that don't get caught go the aquarium trade]. If it's known that, say, 3month old fish that haven't reached a certain size doesn't make for good size in future, then it would make sense to "cull" those fish that are too small - and what better way to cull them than to sell them for money to the aquarium trade (and anyone who's been breeding fish for a while know that some fish are ALWAYS going to be runts, while others are growing better - whatever the cause for that is).

But this is still jsut a guess! I don't know anything about the farming of Pangasius or how they are selected for the aquarium trade - but most likely is that the ones that find their way to the LFS were originally intended for a cooking-pot.

I still think it's not a great idea to keep fish that would potentially grow much larger than anyone but the very rich can afford to house [the cost of keeping 10000 gallon tanks is not small, whatever income you are on] - because these fish SHOULD grow a lot larger than a foot, and there's no guarantee that ALL specimens choosen for the aquarium trade will NOT grow large!

--
Mats

[Barbie]

Michael I was addressing the original poster, not your argument. Sorry for any confusion my disagreeing with your opinion might have caused. Starvation or poor living conditions can stunt horses, so that they are distinctly smaller than normal and up to the age of 4 or 5, you can still attain a close to normal size if you correct the issues. There's no real way to determine that a fish hasn't been chemically or otherwise stunted either in a tank, or when wild collected, without actually evaluating the living conditions, IMO.

Which still goes back to the question of why? When there are so many other fish out there appropriate for the size of glass boxes most of us keep our fish in, why torture one that cruises constantly and is very likely not going to attain it's genetically possible maximum size?

I'm big on keeping fish with hard to recreate environmental needs, but pangassius aren't just going to be more difficult unless you happen to own a large tropical pond!

Barbie

[Moontanman]

I have to admit that even with the type of stunting I am talking about we are still talking about aquariums over 100 gallons minimum and since very few people are capable of maintaining fish tanks this large it is still a moot point but it does have relevance in the real world. I was told that my fascination with bonsai might be the reason I don't have a problem with raising a fish that is "less than it can be!" and maybe this is true but I still want people to under stand I am not talking about stunting the fish by abusing it. The fish I had was obviously never abused. It was not only healthy and alert it also hadn't torn it's self up by crashing into the sides of the aquarium like iridescent sharks are much prone to do. This fish was something special in some way. My 45 years of keeping fish tells me this in a way that is difficult to communicate. Also it has implications in other fish. Some fish are easier for this to happen to than others. Gold fish are among the easiest, I would say that iridescent sharks are among the hardest. It would also appear that our hobby judges the suitability of a fish for captivity simply by looking at the maximum adult size of a fish. If this were true then many of the fish we keep would be off limits to us. Black sharks which are supposed to get huge but almost never do so. Goldfish which are commonly kept in small bowls but since they are supposed to get well over a foot long (about 18") there would be no gold fish in bowls even though a great many are kept this way with quite a bit of success. I know my mom had a gold fish in a bowl when she was a kid. She kept it for many years on the night stand beside her bed. Lots of other fish come to mind that have an adult size of more than 12" but almost never see much more than 3 or 4 inches. I remember the first time I saw kissing gouramis at their true adult size, I was stunned to see a fish around 18" long. I had in many years of not only both keeping and breeding fish but operating petshops never seen one any bigger than 6" and I had thought that was freakish. So lets be fair here. If we are going to require that all fish reach their maximum adult size quite a few fish will have to be rolled back unless they can be kept in a 70 gallon or bigger tanks and even then they would have to be alone. When was the last time you saw an 8" molly? 6 to 8 inches is the true adult size, I've collected them from the wild that big. This no stunting rule has to apply to both the very large and the smaller fish as well. If we applied this rule to all fish it would have far reaching consequences we would not like very much. I think that if the fish farms that raise iridescent sharks knew how serious a problem this was they would really be breeding for smaller fish for aquariums. Who knows maybe this is already underway and I saw some of the early results of this work. Let's not throw the baby out with the bath water and keep an eye on baby!

Michael

Michael I was addressing the original poster, not your argument. Sorry for any confusion my disagreeing with your opinion might have caused. Starvation or poor living conditions can stunt horses, so that they are distinctly smaller than normal and up to the age of 4 or 5, you can still attain a close to normal size if you correct the issues. There's no real way to determine that a fish hasn't been chemically or otherwise stunted either in a tank, or when wild collected, without actually evaluating the living conditions, IMO.

Which still goes back to the question of why? When there are so many other fish out there appropriate for the size of glass boxes most of us keep our fish in, why torture one that cruises constantly and is very likely not going to attain it's genetically possible maximum size?

I'm big on keeping fish with hard to recreate environmental needs, but pangassius aren't just going to be more difficult unless you happen to own a large tropical pond!

Barbie

[Bas Pels]

I have to admit that even with the type of stunting I am talking about we are still talking about aquariums over 100 gallons minimum and since very few people are capable of maintaining fish tanks this large

I don't know how many liters go in a gallon, but i got 4 tanks over 1000 liters, and 4 more between 500 and 1000. I think thay are all over this 100 gallons

I was told that my fascination with bonsai might be the reason I don't have a problem with raising a fish that is "less than it can be!" and maybe this is true

This could very well be the case. However, plants do not suffer (the have no nerves) but animals do. I can trim my hair, but not my fingers

but I still want people to under stand I am not talking about stunting the fish by abusing it. The fish I had was obviously never abused. It was not only healthy and alert it also hadn't torn it's self up by crashing into the sides of the aquarium like iridescent sharks are much prone to do. This fish was something special in some way. My 45 years of keeping fish tells me this in a way that is difficult to communicate. Also it has implications in other fish.

I fact you say you were lucky, were you not?

Some fish are easier for this to happen to than others. Gold fish are among the easiest, I would say that iridescent sharks are among the hardest. It would also appear that our hobby judges the suitability of a fish for captivity simply by looking at the maximum adult size of a fish. If this were true then many of the fish we keep would be off limits to us. Black sharks which are supposed to get huge but almost never do so. Goldfish which are commonly kept in small bowls but since they are supposed to get well over a foot long (about 18") there would be no gold fish in bowls even though a great many are kept this way with quite a bit of success.

Please, by comparing your Pangasius with goldfish, you are undoing whatever you managed to reach before. I am not an animal liberator, I eat meat, but I would be in favour af a legal ban forthese tortuous devices.

Your mother did not know better, but you do

I know my mom had a gold fish in a bowl when she was a kid. She kept it for many years on the night stand beside her bed. Lots of other fish come to mind that have an adult size of more than 12" but almost never see much more than 3 or 4 inches. I remember the first time I saw kissing gouramis at their true adult size, I was stunned to see a fish around 18" long.

my conclusion is that the kissing gouramies are missing something - in this case I know they are planton feeders, and thus need a murky tank, nobody provides them

I had in many years of not only both keeping and breeding fish but operating petshops never seen one any bigger than 6" and I had thought that was freakish. So lets be fair here. If we are going to require that all fish reach their maximum adult size quite a few fish will have to be rolled back unless they can be kept in a 70 gallon or bigger tanks and even then they would have to be alone.

You will not be surprised I can easily mention a lot of fishes unsuitable for any tank less than 1000 liters, but very well suited for a tank of 2000 liters.

When was the last time you saw an 8" molly? 6 to 8 inches is the true adult size, I've collected them from the wild that big.

I know some varieties do, but others do not. In fact i do have a few wild-form mollys, the biggest reaching 10 cm. Many, many rivers don't have mollys larger than that.

If I have a variety which is 10 cm in the wild, it should grow to 10 cm. I can understand people take the small varieties home, because they will require smaller tanks

This no stunting rule has to apply to both the very large and the smaller fish as well. If we applied this rule to all fish it would have far reaching consequences we would not like very much. I think that if the fish farms that raise iridescent sharks knew how serious a problem this was they would really be breeding for smaller fish for aquariums.

Sorry, I don't think they will botter, arguing: the fish we keep will life 4 months more, the fishes we sell will life a year more. no complaints for them.

Who knows maybe this is already underway and I saw some of the early results of this work. Let's not throw the baby out with the bath water and keep an eye on baby!

I don't really know what you mean with this, but I do know here, in Europe, many people point at goldfish, saying (righfully) this is wrong, so keeping fishes is wrong.

Of course, tis is no correct way of reasoning, but it does convince people.

Perhaps I'm thinking a bit too much about well being for fishes, because I want these people not to forbit my hobby

Bas

[Moontanman]

We are operating on two different paradigms here, I think it's not only ok for captivity to impact a fishes maximum size in a downward way, it's inevitable. You on the other hand say it's not only possible to not to impact a fishes life negatively but if we are responsible fish keepers the greenie nuts will leave us alone and go after the real bad guys, nukes or coal or whatever is the flavor of the month for doing something about. I've got news for you, the nut cases are not going to be happy until there are no pets at all and we are all squatting in caves trying to figure out what the fuss was over civilization anyway. If you are going to oppose keeping big fish please do it for reasons that make sense, not to please a bunch of whacked out peta people who don't care what you do to appease them. Take the issue by the horns and tell me I'm an evil so and so because I want to keep over size fish in a small tank not because you want to keep peta off your back. Here in the states we are opposing peta directly by getting animal organizations to recognize the dangers of the ridiculously far left by telling people what their agenda really is. "The complete destruction of civilization as we know it!" so call me names if you wish, tell lies on me if you must but don't let the fear of peta keep you from confronting me directly!

Michael Hissom

I have to admit that even with the type of stunting I am talking about we are still talking about aquariums over 100 gallons minimum and since very few people are capable of maintaining fish tanks this large

I don't know how many liters go in a gallon, but i got 4 tanks over 1000 liters, and 4 more between 500 and 1000. I think thay are all over this 100 gallons

I was told that my fascination with bonsai might be the reason I don't have a problem with raising a fish that is "less than it can be!" and maybe this is true

This could very well be the case. However, plants do not suffer (the have no nerves) but animals do. I can trim my hair, but not my fingers

but I still want people to under stand I am not talking about stunting the fish by abusing it. The fish I had was obviously never abused. It was not only healthy and alert it also hadn't torn it's self up by crashing into the sides of the aquarium like iridescent sharks are much prone to do. This fish was something special in some way. My 45 years of keeping fish tells me this in a way that is difficult to communicate. Also it has implications in other fish.

I fact you say you were lucky, were you not?

Some fish are easier for this to happen to than others. Gold fish are among the easiest, I would say that iridescent sharks are among the hardest. It would also appear that our hobby judges the suitability of a fish for captivity simply by looking at the maximum adult size of a fish. If this were true then many of the fish we keep would be off limits to us. Black sharks which are supposed to get huge but almost never do so. Goldfish which are commonly kept in small bowls but since they are supposed to get well over a foot long (about 18") there would be no gold fish in bowls even though a great many are kept this way with quite a bit of success.

Please, by comparing your Pangasius with goldfish, you are undoing whatever you managed to reach before. I am not an animal liberator, I eat meat, but I would be in favour af a legal ban forthese tortuous devices.

Your mother did not know better, but you do

I know my mom had a gold fish in a bowl when she was a kid. She kept it for many years on the night stand beside her bed. Lots of other fish come to mind that have an adult size of more than 12" but almost never see much more than 3 or 4 inches. I remember the first time I saw kissing gouramis at their true adult size, I was stunned to see a fish around 18" long.

my conclusion is that the kissing gouramies are missing something - in this case I know they are planton feeders, and thus need a murky tank, nobody provides them

I had in many years of not only both keeping and breeding fish but operating petshops never seen one any bigger than 6" and I had thought that was freakish. So lets be fair here. If we are going to require that all fish reach their maximum adult size quite a few fish will have to be rolled back unless they can be kept in a 70 gallon or bigger tanks and even then they would have to be alone.

You will not be surprised I can easily mention a lot of fishes unsuitable for any tank less than 1000 liters, but very well suited for a tank of 2000 liters.

When was the last time you saw an 8" molly? 6 to 8 inches is the true adult size, I've collected them from the wild that big.

I know some varieties do, but others do not. In fact i do have a few wild-form mollys, the biggest reaching 10 cm. Many, many rivers don't have mollys larger than that.

If I have a variety which is 10 cm in the wild, it should grow to 10 cm. I can understand people take the small varieties home, because they will require smaller tanks

This no stunting rule has to apply to both the very large and the smaller fish as well. If we applied this rule to all fish it would have far reaching consequences we would not like very much. I think that if the fish farms that raise iridescent sharks knew how serious a problem this was they would really be breeding for smaller fish for aquariums.

Sorry, I don't think they will botter, arguing: the fish we keep will life 4 months more, the fishes we sell will life a year more. no complaints for them.

Who knows maybe this is already underway and I saw some of the early results of this work. Let's not throw the baby out with the bath water and keep an eye on baby!

I don't really know what you mean with this, but I do know here, in Europe, many people point at goldfish, saying (righfully) this is wrong, so keeping fishes is wrong.

Of course, tis is no correct way of reasoning, but it does convince people.

Perhaps I'm thinking a bit too much about well being for fishes, because I want these people not to forbit my hobby

Bas

[racoll]

I think the stunting issue is a bit of a sideline really.

I think some fish are suited to life in a aquarium, and some are not:

For example many Apistogramma are born, reproduce and die in an area the size of a dinner plate. They also have a short life-span of no more than a few years. They live amongst leaves and eat insect larvae. They are perfect fish for an aquarium.

Pangasius however are massive, long-lived migratory fish that dwell in vast turbid flowing rivers. They are active, shoaling predators/scavengers that patrol huge areas of water.

It doesn't take a genius to work out that they will not generally do well in a tiny glass box. The fact that almost all die very quickly in captivity is testament to that.

There is a grey area between these two cases, and it is up to individual aquarists to make up their own minds.

Planet Catfish is here to provide information to help people to make an informed choice.

[sidguppy]

I second Racoll in this.

very clear written, that one.

There is a lot of "grey" in the ethical aspect of the hobby.
it's most definitely not a matter of black and white, of yes and no.

For me, say, my personal opinion is that fishes bigger than, say, 2 or 3 feet are completely unsuitable for any hometank.
but that's not the whole story.....

a migratory fish that lives in huge shoals, only eats plancton and reaches 1.5 foot might very well be unsuitable (like some freshwater Herring species), but a 3.5 feet eel (like the Fire eel Mastacembelus erythrotaenia) can be kept in a big tank without much difficulties.....

so even in these 2 examples you can see that my old rule about fishlength is bogus when it comes to certain fish.

but fishes with significant bodymass, a migratory lifestyle, shoaling social behaviour and a length past 3 feet have all the characteristics that make them fine for the fisheries and consumption, but very very unsuitable to be kept alive in an aquarium.

nobody in his right mind would try to keep a Great White Shark in a home tank. or a small harbour porpoise for that matter.....
still, both animals get born as small, less than 2 feet in length. smaller than an adult Acanthicus hystix! does this make them suitable for the hobby?
NO

does a slowmoving bottomcrawler like the Acanthicus make a hometank fish? well, if you're dedicated enough to set up a tank that's 1 m wide and 3m long, yes, it will. and there are hobbyists with tanks like that. not many, but they do exist.

our hobby is into "grey ethics" for the most part.
if it's turned into a black and white issue just because the topic isn't important anymore, but only the "winning of the discussion" we might as well quit fishkeeping alltogether.
and eating fish.
and burning rainforests
and breathing and multiplying.

by turning it into a "black and white/all or nothing" discussion, just because you might use these tactics to "win" then I dare challenging you that the best you can do -ever!- for the fishes is to commit suicide.
cause -in a black and white world- we humans are the worst kind of vermin from any fishes' kind of view!
so to placate the fishes in the truest way possible, you really should stop living alltogether.

now, that would be utterly nonsense and stupid, see?
so we MUST look at our hobby as "grey", not "black and white".

[bronzefry]

Just so that I'm not lost here, are we speaking about the same Pangasius hypophthalmus that can grow to 51.8" in the Mekong basin? Or, am I thinking of a different "Iridescent Shark?" I get confused with commong names.
Amanda

[racoll]

Correct Amanda, we are talking about

Pangasius hypophthalmus

.

However it may be that Moontanman's fish was one of the other smaller

Pangasius

species, although i doubt they are found in the aquarium trade.


Is there a possibility that the food farmed Pangasius are selectively bred to be much smaller? There could be many reasons for this such as for example....

* Larger fish taste worse
* Smaller fish grow at a faster rate to saleable size
* Can cram more in a pond
* Diet changes as they grow larger

Some factors to think about.........

[Moontanman]

Yes I am pretty sure it's the same one although I was under the impression it was one meter (39.73" or close) but the effect is the same a very large heavy fish that you could make a fortune from if you could breed a small one of! But no that isn't my agenda.

Michael

Just so that I'm not lost here, are we speaking about the same Pangasius hypophthalmus that can grow to 51.8" in the Mekong basin? Or, am I thinking of a different "Iridescent Shark?" I get confused with commong names.
Amanda

[Moontanman]

I am pretty sure my fish was Pangasius hypophthalmus but I know there is a mutation that occures in some fish that when this mutation is expressed the fish never reaches more than fraction of it's normal adult size. And while this mutation can cause some discoloration and the fish I had was discolored slightly I have no real evidense for this mutation. Since I almost never keep large fish it is unlikely I will ever know the causes for this. As far as I know no others are interested in finding out about this.

Michael

Correct Amanda, we are talking about

Pangasius hypophthalmus

.

However it may be that Moontanman's fish was one of the other smaller

Pangasius

species, although i doubt they are found in the aquarium trade.


Is there a possibility that the food farmed Pangasius are selectively bred to be much smaller? There could be many reasons for this such as for example....

* Larger fish taste worse
* Smaller fish grow at a faster rate to saleable size
* Can cram more in a pond
* Diet changes as they grow larger

Some factors to think about.........

[MatsP]

Correct Amanda, we are talking about

Pangasius hypophthalmus

.

However it may be that Moontanman's fish was one of the other smaller

Pangasius

species, although i doubt they are found in the aquarium trade.

Whilst the Cat-eLog shows a few species that don't grow very large, two of those are missing a nought on the end of the number, so not 80mm, but 800mm and not 100 but 1000mm for the two shorter ones. The only one that isn't listed as "large" is P. macronema, but the picture in the Cat-eLog appears to show a fish slightly larger than the 300mm listed [assuming it's a 300mm ruler - which is the common size].

Is there a possibility that the food farmed Pangasius are selectively bred to be much smaller? There could be many reasons for this such as for example....

* Larger fish taste worse

Yes, undoubtedly. However, the size that you sell the fish at has nothing to do with it's ultimate size - Salmon can grow to abour 15-20kg, but you rarely see fish above 3kg in the shops - because that's the suitable size to sell them, and they haven't become too tough to eat

* Smaller fish grow at a faster rate to saleable size

In my opinion, fish with an ultimately larger size would grow faster as small individuals than those with a smaller final size - but I could be wrong.

* Can cram more in a pond

That's dependant on their "current size" and "growth-rate", not their ultimate size.

* Diet changes as they grow larger

Yes, that's a possibility.

Some factors to think about.........

[racoll]

Yes, those ideas were just off the top of my head, and they don't necessarily make sense.


I was just wondering why someone would selectively breed Pangasius to be smaller.


Perhaps they are bred small solely for the aquarium trade, if indeed they are....?

[MatsP]

Actually, my suggestion (which probably where the "breed smaller" idea came from) was rather that in all populations, there's a variation in size and growth-rate. If you were a aqua-farmer that grow Pangasius for the purpose of selling to the food industry, and you have a choice of "selecting" a few fish for the aquarium trade, how would you go about selecting those? Pick the small "runt" ones comes to mind to me... Particularly since the customer isn't exactly going to complain if they are slow growers and don't reach a great size quickly. But this is PURE SPECULATION!

I'm by no means saying the farmer was originally setting out to grow them smaller - as a commercial entity (which I think all of them are), they want the best growth per dollar spent, and slower growing fish costs more if nothing else because they still need the water maintained for the time it takes to grow to saleable size.

--
Mats