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how many sterbai cories can I put in my 55 gallon tank? (no other inhabitants). Thanks!

About 25-30 or so - but that's based on the "one inch per gallon" basic principle, which isn't a very good way to determine how many fish you can/should keep in a certain tank.

However, the actual number you can keep depends on several factors:
1. In Cory and other catfish species, the substrate area is more important than volume of water, as the fish are essentially bottom living and thus need space at the bottom, so a 4' x 13" bottom space (as in a 55g) that is 12" instead of 21" tall would suit just the same number of Corys - but the former would be about 30g in size.

2. Aeration which in turn is related to the surface area of the tank. The dissolved oxygen levels will be determining how many fish you can keep in the tank (although Corys are definitely more tolerant to low oxygen levels than many other fish - they can use atmospheric oxygen if the dissolved levels aren't high enough to sustain them).

3. Filtration - number and size of fish sustainable in the tank will depend on the filtration system and it's efficency - if a spike in ammonia remains because the filration isn't coping, the fish will suffer.

4. Water change policy and water quality. Since the final compound of "fish waste products" is nitrate, the number of fish you can keep is determined by the nitrate levels in the tank. Anything above 50 ppm starts to be bad, and above 100 is definitely a no-no. Ideal is below 20 ppm. If you change water 40% of th etwice a day [with water that has 0 ppm nitrate], you can keep many more fish than if you change 10% of water once a week or once a month...

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Mats

ok so um:
1. the substrate that I am using in gravel only one step above sand.

2. I have a bubbler in the tank.

3. amonia hasn't been spiking for the past two months

4. 3ppm nitrate

so how many thanks?

No, what I'm saying is that there's no absolute formula to calculate the number of fish in a tank - not that you need to supply more information... The only way to determine the max stocking of a tank is to stock it until it's no longer able to cope with the current stock, and then cut back a bit. [This becomes more troublesome if you haven't got adult fish to start with, as the fish growth will increase the stocking level by itself].

By the way, by size of substrate, I meant the AREA of bottom of the tank, not the grain-size of the actual substrate material. Sorry for the confusion.

Also, it's unlikely that you will see a spike on ammonia unless you overload the filter - there WILL be spikes of ammonia, as the production will be ahead of consumption - even if it's VERY SMALL and VERY SHORT. And until you go beyond what the filter can cope with, you shouldn't see any ammonia spikes.

If the tank is "empty", the nitrate level should be very low.

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Mats

Do you think I should start with 6 or 8? Thanks! 1 more question. can they go with pictus cats?

6, 8, 10, 12, 15 would all be fine numbers to start with (assuming the tank is fully cycled - if you're planning on cycling the tank, I would suggest some less expensive and somewhat less fragile fish, such as C. aeneus or Guppy/Molly of some sort that are hardy enough to survive the ammona/nitrite spikes that will occur as you add the fish).

Also, unless there's decent stock in the tank already, don't add 15 corys at once, get a few and then add a few more, maybe 5 to begin with, then wait a week or two before you add the next 5 and so on.

And yes, as long as the corys arent too small in relation to the P. pictus, they will go along fine - I have 5 P. pictus with 5 C. sterbai in my big tank (along with some 20 or so other fish).

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Mats

sry 1 more Q. can I put the cories with a BABY senegal bichir or even an adult? Thanks!

Reptilian wrote: can I put the cories with a BABY senegal bichir or even an adult? Thanks!

That's a big NO.

they'll get eaten? oh. don't want that. I was just readin a post on here that said

corydoras that are simialar will school together

what other cories are similar enough to school with c.sterbai? thanks!

Can't really think of many (common) Corys that are similar to C. sterbai. is the only one that comes to mind at all, and I don't think it's very easy to find those.

Why you would want to do that is not clear to me - I'd much rather have more of one sort than to have several very similar fish in my tank(s). [Like I actually follow that guideline myself ]

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Mats

idk jw. so the similar thing only has to do with color and pattern and body type? wow I thought it was all internal. lol. thanks!