fish flickering

[verboten53]

Hi,

I am a new member. I have a 55 gallon freshwater tank. Recently added six koi each about 5.5 inches long. Noticed that two of them (after about a week0 and a 30% water change, were bouncing off the gravel bottom and the glass every once in a while. Could not see any evidence of disease. It is possible they picked up some parasites from the three fish I had already in the tank. Lost some fish previously but did large water changes then. Tested water quality just now and , nitrate was 5.0, PH 7.6, nitrite was zero, ammonia was zero and high Ph was 7.4. so water looks ok now. Fish are all eating well but one seems to have a bent tail and looks a bit skinny and frail. Floats at the top of the tank but still eats. Wonder if he could be infecting the others. He was an original fish and the 6 were introduced. Today fish appear ok with a little flickering now. Should I treat the tank with anti parasite medicine called PraziPro or just sit back and wait and continue to change water 25% each week? BTW water temp is 63. Total of nine fish in the tank.

Your thoughts?

Also have a 29 gallon tropical tank and a 50 gallon pond outside currently shut down for winter. Plan to add Koi this spring.

Had this hobby on and off since I was 12 years . Now 55!

Thanks for any views you may have.
Rog

 

[joy13]

Parasites can live for quite awhile in a tank and will attack stressed fish. It is very likely you might have some type of parasite such as ich or velvet living in the tank. I have never treated any koi or goldfish for anything, so someone else is going to have to jump in on what to treat them with and how.

 

[beglely]

I have been fighting this problem for a long time...I rarely see flashing anymore but the gold dust on the fish is quite obvious--wont seem to go away. Ive raised the temperature on the tank like most people advise but it doenst seem to phase it. I have medication but i dont want to kill my inverts on here so I seem to be at a loss here. Its more than likely velvet, but im still at a loss on how to combat it properly