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Dear All

A few days ago I bought a pair of C. sterbai. These are the first corydoras I have kept in over 15 years. The problem is, all they do is incessantly swim up and down the sides of the tank, as if trying to get out.

Literally, ALL they do is swim up and down, back and forth against the glass.

I hate this unsettled behaviour in fish, and keep hoping that they are just settling in, but it has been four days now and they have not stopped. They have got a lot of stamina!

Is this normal with new Corys? Are they still settling in? I can discount poor water quality and bullying from tankmates - both of these are not issues.

The tank is 24" deep. Might this be an issue for them - are they trying to get to shallower waters? I don't know. The only other thing I can think of is that they are insecure as just a pair. But I bought only a pair to see how they'll do, hoping to add to the shoal if the first two settled in....I may be in a vicious circle here...

What I do know is that if this behaviour doesn't stop, I'll have to take them back to the shop. They're obviously not happy.

Any input, as ever, would be much appreciated.

Thanks

Joe

I'm pretty sure that within a few days, they will have settled down. It's fairly common for corys to be a bit "hyper" like this when they have just been introduced to the tank. It would probably help them if you keep more than a pair - they like to be in a group - mine are between 4 and 8 per tank in three different tanks - I will shuffle some of them around in the near future to make a larger group in the tank with 4, but I've got some other fish to shuffle before the corys can be put together in one tank. This applies to ALL corys - in nature, they live in shoals of hundreds or thousands. They do not feel particularly comfortable on their own.

I'm 100% sure that a 60cm/24" deep tank is not a problem - I keep C. sterbai and C. similis in a RIO 400, which is about 60 cm from top to bottom - and I've read that Corys live in water that is far deeper than 60cm from time to time - sure, they commonly also live in small drainages that are less than a feet deep, but they certainly can survive in both shallow and deep water.

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Mats

Thanks Mats - that's great info. I am very tempted to get 2 more to bring their numbers up. I think I'll be patient, wait a couple more days and see what happens. Was particuarly heartened about the height issue - this did have me worried, but no longer.

Thanks!

If you can, I'd suggest you get at least another 4 - they really do best in a group of at least 5, where 6 is better. I don't actually buy corys in lower numbers than 6 (unless I've had some sort of accident).

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Mats

MatsP wrote:It's fairly common for corys to be a bit "hyper" like this when they have just been introduced to the tank.

I'd agree with Mats here- if I change any decor in any of my tanks (usually unintentionally and only fractionally, after a thorough gravel vacuuming) or if I move any of my corys to different tanks, then for several days they explore the tank in a distinctly hyper, stressed-looking way. The behaviour seems unrelated to numbers- my 4' tank has 14 Brochis splendens in it, and if anything they seem to set each other off with this behaviour (albeit, as Mats suggests, long-term, corys are happier in groups than as singles/pairs/trios). After a few days my various corys settle back to being fairly inactive most of the time. The fact that sometimes the change in decor is miniscule, yet produces the same effect, might suggest something about how corys "learn" a home range, although I'd have thought that fish in the wild ranged over too big an area to truly learn an aquascape.

On a couple of occasions, this hyper exploration phase of a new environment has led to fish spawning- my sterbai and Brochis both spawned whilst looking stressed in fairly new environments for them.

Well on Friday I returned to the shop and picked up another 3 sterbai.

Now I have five catfish driving me crazy with this swimming up and down, back and forth behaviour!

But I am heartened by what you have both said, and am confident (fairly) that they will settle down. Here's to patience patience patience.

Thanks for your input,

Joe

I have over 40 cories.

Those so call hyper cories have the proper behaviour and are actually good for them when they are ready to breed.

I have 5 C panda and 1 C panda is always swimming everywhere. As for my Stebai Cory, they are always resting.

I dont see a problem with active cories, i only scare of passive cories =)