Topaz Puffers

[fishman 30]

I have just added two topaz puffers to my fresh water 30 gallon tank. Ive been told that they are ok to live together and ok in fresh water.

I added them yesterday one is fine swimming around, the other one is motionless, just twiching a fin, the well one seems to go to the sick one almost out of concern and rub against him. not aggresivly but very gently.

when the sick one went in the tank he was ok, he went mad bouncing off all the sides and then just lay there. worried he's goona die in under a day!

The nitrite levels are 0 and amonia 0 temp 26.

Not sure what to do?

Advice please

 

[nmonks]

Greetings. These are Tetraodon fluviatilis, or something closely related (the taxonomy is confusing and not really relevant to your question). They are brackish water fish, at least as far as aquarium maintenance goes, and cannot be kept in freshwater tanks for long. When kept in freshwater for more than a few months they become steadily less healthy, and far more prone to opportunistic diseases such as fungus and finrot.

Tetraodon fluviatilis are big (upwards of 12 cm in length) and fairly aggressive, and I suspect you'll find a 30 gallon tank too small once they mature. But assuming they're still small (say, under 10 cm in length) you should be okay in terms of aquarium size and filtration.

Your main job is to ensure that the water in the tank is hard, alkaline, and brackish. You're aiming for pH 7.5-8.2, hardness upwards of 10 degrees dH, and a salinity of SG 1.005 (or about 9 grammes of marine salt mix per litre). Do understand you need marine salt mix, not cooking salt, tonic salt, aquarium salt, or anything else you wouldn't put in a reef tank.

Much is written about these puffers; my FAQ is as good as any place to start!

Cheers, Neale