Dying Zebra Danio (Glofish)

[BettaBoysGirl]

Today, As I was watching my fish, I noticed I was missing one. I went on a Hunt in my tank to discover the one that was missing, laying near the bottom of the tank, alive, but lethargic and extremely thin. Im pretty sure I am going to lose him. He sometimes just float to his side, as if he is dying. Anyhow, I have had Him for nearly 2-3 months now (Cant tell with my glofish, Hard to tell them apart). The tank was cycled fishlessly before he was ever added. All the others are doing fine, but I am trying to figure out whats wrong with him, so I can stop it from happening to the others. He will not eat. He has no bent spine. His tank is a 20 gallon that consists of 5 panda Cories and 9 Glofish (including the sick one). Well I watched him in the tank after I discoverd him and he came up and swam some, but was slower then the others. I pulled him out and have him in a hospital tank. Any idea whats going on? Other then sympotms listed above I have no idea whats wrong with him. Any ideas would be appreciated, in the quest to possibly save the others (mind you they all look quite healthy and energetic).
Readings were
72º F
0 Ammonia
0 Nitrtite
10 Nitrate
Ph is 7.8

 

[The-Wolf]

it is a sad fact that danios are so interbred that you often come accross one or two that just
dont have a good enough gene pool to live a full and healthy life.
if you feel it is suffering then my only advise is to do the kindest thing and end it.

 

[BettaBoysGirl]

I ended up losing the one. Now, I have another, while swimming at the top, not looking that lethargic, wont eat! I think somethings seriously wrong with my tank. any suggestions!

 

[The-Wolf]

your water stats look fine but the temp, although within range is a little bit on the low end.
I have found danios do best in the 23-25c range (74-77f)

how old is the tank? less than a year look up new tank syndrom, more than 5 years look up old tank syndrom.
other than that if there is an unknown toxin in there then partial water changes daily will help dilute it.

 

[BettaBoysGirl]

your water stats look fine but the temp, although within range is a little bit on the low end.
I have found danios do best in the 23-25c range (74-77f)

how old is the tank? less than a year look up new tank syndrom, more than 5 years look up old tank syndrom.
other than that if there is an unknown toxin in there then partial water changes daily will help dilute it.

It is under a year. About 5 months old. But was totally cycled without fish before I ever put a fish in. The temp is a compromise between the Glofish and Cories.
The more i've look at other sites, post, and what not. Im concerned it might actually be an internal parasite. I dont feed them live food. I feed them tropical flakes (not much) just because they aggrivate the panda cories I have by going after their shrimp pellets and occasional the algae tabs. The first two weeks I had them, I would wake up in the morning to them being fat, and by afternoon they were normal. Since i decreased their flakes (to even out what they were eating from the cories) it stopped. The one I lost today, did poop, while the feces was still brown it was very pale. (not sure if this was becasue it sat in water for a few hours before my discover). Every one else is doing fine, swimming around normal except One of the yellow GloFish (zebra Danio). He is thin, and not eating, but is swimming normally. I've got him in a floating breeder trap so I can watch him more closely at the moment.
Anyhow, My new question is, If it is internal parasite, how should i treat it? I know cories can be sensitive to medicine. I kinda want to treat the whole tank, just in case they all have it, and my hospital tank seems hard to treat when most meds are for 10 gallons or more, and my hospital tank is a 5 gallon. Also, I have had these fish for awhile. I figured after a month you are in the clear. Is this not true for everything?

 

[The-Wolf]

what you need, if it is internal parasites, is any medication that contains Flubendazole.
Flubenol 15 and Fluke M (NT Labs) sring to mind as the two leading brands.

Flubendazole is safe for all fish however any snails will most likely be erradicated by it.