Tropical Fish Forum
Tropical Fish Keeping Help and Advice => The Emergency Room => Topic started by: Colin on July 07, 2014, 07:21:06 PM
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I have two Corydas Sterbai that have happily been in my tank over the past nine months but all of a sudden they are now hiding inside an artifical log and don't appear to move around as they used to. So my questions would be is this behaviour normal, could they be breeding or have I got a real problem?
Other fish in the 125 litre tank are swordtails, mollies, tetra and pencil fish but they have always been great in each others company, however, after a recent bout of hot weather I have lost quite a few mollies to swim badder issues and as a result have had to use some recommended treatments to get on top of this.
Hope this finds someone who can help.
Colin
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It could be they don't like the meds you used.
Or they could be unhappy with just the two of them - they are shoaling fish and you need at least 6 cories of the same species.
They should be OK with the warm weather as sterbais are just about the only cory that likes warm water.
They won't be breeding. Cories lay their eggs on things - the glass, the filter, leaves etc. The males chase the females round the tank, they assume the T position where the female nuzzles the middle of the male, then she lays her eggs one at a time.
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Thanks for that feedback Sue and I'll monitor their progress following a water change today. They've not had any mates of the same species since they were bought so was a bit surprised by the recent activity especially aas one of them just seems to be facing upwards all the time instead of lying flat but as you say the chemicals may have played a part. I also added aquarium salt in an effort to help the mollies so perhaps they didn't like that either, however, in my defence this was following advice at a specialist store.
Colin
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Here's a quote from The Skeptical Aquarist (http://www.skepticalaquarist.com/corydoras-genus) that has a very good article on cories:
Cories are sensitive to medication. Years ago, when tests were done to test the salt-tolerance of freshwater fishes, Corydoras died first.
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Cories are one of the salt intolerant species, as Colin has said. Don't believe everything a shop tells you.
Mollies are hard water fish, and like a high pH. They can suffer if kept in water that's too soft and acidic. A lot of people believe they need salt in their water but this is not strictly speaking true. They need a lot of the stuff that makes water hard rather than plain salt. Marine salt can be added to their water - in fact some types of molly can live in full strength sea water - but this is not plain salt but a mixture of several salts.
But cories can't take a lot of salts of any type.
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Thanks indeed for the sound advice and the article proved to be very interesting reading. Glad to say that both fish appear to be now acting more normally around the tank now but will keep monitoring and avoid the salt treatment in future.