Cory help

[elgecko]

I'm posting this for my sister who is having problems for some reason keeping corys. I know people will ask water conditions, so I will have to e-mail her for that info. Her bottom is small, round, smooth pebbles. What is happening is that the barbs on the corys "fall off". One day you look at them and notice that they are gone. Shortly after this happens they die. The fish store told her she might have a disease in the tank that only effects her corys. She had waited a month or so before trying to get more corys, after they all died, with the same results. All her other fish many platys, mollies, and tetras are doing great. Anyone have any kind of idea?

 

[Fish Hunter]

Does she clean her small round bottom
Anyway I mean does she clean the gravel when she does her water changes or is she just changing water. Toxins build up in the gravel when it is not clean for long time. Since it is in the gravel the bottom feeders such as corys get sick.

 

[famman]

It's the gravel combined with poor water quality. Barbel rot is a frequent problem with corydoras. Nitrates should be kept under 20 ppm, but don't bring it down from a high level to 20 all at once.

Do a very thorough gravel vacume along with 1/3 water change.

Perform 1/3 water changes at least once a week until the nitrates are below 20.

You may want to treat for fin rot.

You need to remove the small rounded gravel and replace it with the smallest grained gravel you can find, sand works the best.
Dont get sand for salt water tanks, you need silica sand or sandblasing sand, no more than 1-2" deep.
Don't replace all the substate all at once, do 1/3 a week or so.

As long as the pH isn't astronomical like 8.2 or more dont worry about it.

good luck

 

[elgecko]

Well she got back to me with the following info.

Tank conditions... 36 gallon, temp 78-80, pH 7.1, ammonia= 0, nitrite = 0, nitrate <=10. Other fish in tank... 4 platys, 2 mollys, 1 ram, 6 neons, 2 black neons, 1 otocinclus, 2 female bettas. Live plants... rotala, amazon sword, java moss, java fern, cryto. wendtii (sp?). Regular aquarium gravel.

I would not think that to be poor water conditions. I believe she changes 20% of her water every 2 weeks and gravel vac. I'll double check this info.

 

[elgecko]

Update:
She actually does a 25% water change and gravel vac every other week.
She also corrected me on this: not all of the corys I've had have lost their barbels, some have just died within a week to a month or 2 of getting them.
All her other fish have been in the tank for a long time with no problem, just the corys.

 

[OrionGirl]

Is she sure enough food is getting to the bottom for the cories? If they are not getting much food, this could be weakening their immune system, which allows the barbel rot to set in, and the fish starve more quickly since they are fighting the infection. I know with platies, they are pigs, and quick to eat. If she just feeds flake food, there might not be much getting to the bottom. If thi is the case, she can feed algae tabs, and fresh veggies--the veggies will benefit the other fish, as well as the cories.