10 gallon cory question/problem

[F3-RapalaAngler]

I have a planted 10 gallon with Moss balls and hornwort. Spectra stone substrate. It has 3 cherry shrimp, 4 nerite snails and 7 panda corries. Now I have had them for 3 going on 4 weeks and while they aren't as shy as they were the first two weeks, they hide 90 percent of the time and if I come any where near the tank and they are out they go hide in the plants. Water tests fine with a 7.2 ph. No ammonia or nitrite. Is this typical of the panda corries? Do I maybe have too many for a small space? Are they not happy? I've had albinos and they were much more outgoing. It kinda makes me sad and I wonder if I should take them back and get habrosus or pygmy corries for this tank. I don't need them active all the time but it would be nice for at least half the time lol

[shrimpkeeper222]

For me they were super hyper-swimming beside the glass and disturbing shrimps and it was in a 14.gallon tank(tall). I returned the panda cories in like 1 week cuz they were too hyper, and were disturbed my berried shrimps so much. But cories are known to be rather shy in general, and that might be the case there. And yes, they might be in a too much of a small tank. Hopefully someone more expert w ill answer you more accurately though.

[F3-RapalaAngler]

So if there are too many what exactly does that mean? Sorry for my ignorance I just want the fish happy and healthy

[MattArmstrong]

I would agree that one of the pygmy Corydoras varieties may be a better fit for a 10 gallon with shrimp, especially if you're a beginner and prone to lapses in dilligent tank maintenance. Less bio-load in your tank means it can withstand beginner mistakes better.

I would not say your tank is grossly over stocked. The snail and shrimp are low bio-loads. As for fish, there are two "rule of thumb" guidelines that I have seen given for stocking density in your situation.

The first is the "inch per gallon" rule, which tends to work well with normally proportioned tanks (e.g. not the extremely tall ones), housing 1-2" fish like a C. Panda. It would say that a 10 gallon tank can handle 10 inches of fish, or 5 C. Panda (they grow to 2").

The second is specific to Corydoras and suggested by Ian Fuller, with a guideline of 6-8" of Corydoras per square foot of tank bottom. A 10 gallon tank is 20" x 10" -> 1.4 square feet * 8 inches -> 11.2 inches of Corydoras -> roughly 5-6 C. Panda.

So both rules of thumb come out to about the same. These are just guidelines, and going over them a bit is not a huge deal. Just stay on top of tank maintenance, and add no more fish. Corydoras do best in groups of 6+, so I would not intentionally go below that. Experienced fish keepers can successfully over stock their tanks with regularity, but those tanks tend to run "hotter" in the sense that small problems can turn into big problems more quickly.

With respect to them hiding, I've found that Corydoras are more active when happy. Most don't like bright lights. Different species tend to have different habits, too. I've never had C. Panda, so I can't speak from experience.

I've had a group of C. Adolfoi for quite some time and had the same always hiding behavior, but through the year it seems that very minor changes has caused them to shift behavior. E.g. I'd change the location of a filter and they'd move their main hangout location to a different spot, usually with the lowest flow. If the area of the lowest flow is out in the open, that is where they'll hang out. I've also seen a dramatic improvement in their apparent happiness and activity by switching to a 1/2 inch layer fine sand (roughly 1/2 millimeter sand). They are now much more interested in rooting around the tank. Gravel tends to accumulate rotting food and mulm, which can become an area of concentrated bacterial activity, which disproportionally impacts those fish that spend most of their time in contact with the substrate (the dreaded "eroded barbels" problem). Sand tends to leave the food on the surface, where the Corydoras find and eat it easily, and the tank as a whole stays cleaner. I've also gotten rid of plants in the substrate in favor of Java Fern and Anubias on driftwood. The substrate is now "open" and I see the Corydoras more, but they seem to feel about as safe as before. It also seems that C. Adolfoi are "crepuscular", or at least they seem to be most active in the beginning of the day and the end, when the light is dim.

[F3-RapalaAngler]

So I'm a bit confused, my water is perfect, I normally change water twice a week since it's a planted tank but it always tests fine when I do it. Would it be a better move to take back the pandas or roll with them? I've also read pygmy and habrosus corries are very shy and hide a lot. I kinda don't want to change one for another and get the same behavior

Is there a such thing as them feeling too cramped so they're not happy with how many are in the tank?

[MattArmstrong]

Cories typically like to hang out together. My 9 cories bunch up in almost a dogpile in my 50 gallon tank.

I don't know what to recommend. Like I said, my cories change behavior for things I did not think we're significant at all.

Maybe post pictures? Sometimes experts (I am not one) can spot issues that no normal person would see.

[F3-RapalaAngler]

Here's what the tank looks like. Getting pictures of them is hard

[bekateen]

I haven't kept this species of cory, but I do keep several other cory species. Based on the general ideas I have about corys, I look at your tank and think two things:
(1) the corys would much prefer sand instead of gravel, and
(2) the corys would probably prefer a little more background cover (tall plants, driftwood, etc.) and maybe some foreground cover (short plants); this tank is very wide-open and exposed in the middle and right sides, and that may make the fish insecure.

Okay, I have a third thought too. Your tank does look nice.

Cheers, Eric

[F3-RapalaAngler]

They seem to hang out under the plants 90 percent of the time. If I walk anywhere near the tank they run and hide

[bekateen]

I would interpret that to mean that they are startled or scared by your movements, especially if you notice them out in the open when you are nowhere close to the tank, or if you stand or sit still for a very long time and allow them to forget that you are standing nearby; if they are coming back out in the open when you're not around, then that means they don't feel as safe when exposed in the open.

Keep in mind that some corys are more naturally timid than others. My bronze corys wouldn't care if I jumped in the tank with them, but my ambiacus and C141 jump when I so much as breathe near the tank. Again, I haven't kept this species, so I don't know what's normal for them, but it sounds to me like they are scared.

[MChambers]

I've read this thread with interest, because I've never found any consistency in how various types of Corydoras behave. In some tanks, a species will be very active, but in another not so active.

For example, right now I've got about 20 Corydoras sp. C123 in a 30 gallon tank with the only other aquatic animal life (other than microscopic life) being red cherry shrimp. There is plenty of cover, but the Corydoras tend to be quite shy. At times in the past, however, the same Corydoras have been very animated.

So I find it hard to give you any guidance. I do think that a 10 gallon tank is a little bit small for pandas. I also agree that sand is preferable to gravel, but I've had some Corydoras do quite well on small, smooth gravel.

Matt

[Corycory]

Hi,

Generally it is normal for corydoras to have quiet time during the day, hiding in a bunch somewhere. But consistent hiding is mostly due to lack of cover in the tank. Looking at the pictures, yours is too bare. I know that we all have preferences how we want our tank to look and we treat aquariums as furniture but fish have other demands. They prefer tanks that look like a dump site for plants, wooden branches, caves, all the way up to the surface if possible. Even if you don't want a tank like that, try it one day to see the difference in behaviour. Large species of anubias like barteri will take a lot of space and shade the bottom, some crypts can eventually cover the bottom, some wooden branches, caves, etc.. and the corys will be out non-stop. I am talking from experience. I've got a lot of corys(can't count, over 30 maybe) and I've kept them for a good few years. And obviously, they love sand. They bury themselves halfway in it.

[VelcroWY]

As MChambers said, it's hard to predict how corys will behave. Some seem to like to be in the front of the tank and others like to be on the sides or back and some like to hide. It doesn't seem to matter about the species either. I have had aeneus that would run and hide every time I walk by and others that ignore me or even come up to the glass to look at me.