Lethargic fish with no outer symptoms, what do I do?

[ne0heli0s]

I have a Peppered Cory who is behaving very lethargically & will not eat. None of the other five cories are behaving this way. It seems as though Bronze cories (the 3 that I have) are much more active than the 2 peppered cories (including the one in question).

I am prompted to ask this because the cory I am concerned about just floats around very inactively. It can self-right & swim just fine, but seems to "doze off" and will "catch" himself and slowly swim off to some corner or lodge itself between some leaves. Though I know cories are nocturnal, in the 6 months or so that I have had it, the cory has JUST started doing this.

Also, the cory does not eat when I feed the tank (this is the main thing that caught my interest). I had been treating the tank intermittently with an "algae-gone" type product, and it seemed as though both peppered cories might have been grazing on the algae, but the other peppered cory is not exhibiting this behavior.

I keep it in a ten gallon tank with the four other corydoras at work on my desk, and feed them 1/4 tablet of the sinking algae wafer every day during the week (5 days).

I just measured the water quality, and the water is just right for them.

Some internet research suggests this may be constipation, and prescribe salt in the tank. From what I understand, this is a bit controversial.

For now I am simply keeping him in a 1/2 gallon quarantine tank (all I can afford, now), but with no medication, yet. This tank does not have aeration, gravel, or anything; just water and the cory. I plan to perform 1/2 water changes daily until his activity picks up, and then after a couple more days return him to the main tank.

What would you guys suggest I do about my cory?

 

[Sparrow]

Is it possible it could have an internal parasite? try this if this might be the case
http://www.animalworldnetwork.com/julainpagu2o.html

 

[Chaos!]

Your cory will die in that 1/2 gallon tank, so either put him back in the tank or get him somthing much bigger with an aerator and heater.

Have you checked your nitrates? I love half my tank once to a nitrate spike, simply because I didn't think to test for them. I was more concerned about my ammonia and nitrite. However, nitrate is just as deadly at high enough levels. Also, when you say "just right", what exactly do you mean? The symptoms you describe sound a lot like ammonia/nitrite/nitrate poisoning.

Also, you're not feeding them a very good diet. 1/4 of an algae wafer 5 times a week doesn't give them all the nutrition they need. First of all, corys are not really algae eaters--they may occasionally eat it, but it doesn't comprise a major part of their diet. They much prefer meatier foods like bloodworms. Feed your corys a mix of sinking pellets, flakes, bloodworms, brine shrimp and mysis shrimp.

Also, corys need to be in larger groups. 6 is the generally accepted minimum. However, you don't have enough room in a 10 gallon for 6 peppered + 6 bronze, so you either need to pick a species and rehome the other, or bring your numbers up to 4 of each.