The Puffer Forum

did a water change yesterday and thoroughly cleaned ornaments and gravel yesterday. Tank has been up and running for 9 months, salinity 1.010, nitrate and nitrite levels fine.

one fish died during the night but had been looking skinny and poorly for some time. Now the rest of the puffers - 3 are all swimming constantly in water jet and jumping a lot.

any suggestions?

i have just bought a new external filter, not yet fitted, do you think this may help or hinder?

Did you use any detergents to clean the ornaments/gravel? When you cleaned the gravel did you just "hoover" it or did you take it all out, rince etc? If so you may have disturbed some of the good bacteria in the tank which reside in the gravel.

What size is the tank, what puffers are they, and how big?

GSPs 9 months old, so quite small inch and half

tank is 120 litres

just hoovered gravel and used tank water for cleaning ornaments

What are your nitrate and nitrite levels? Ammonia levels?

When was the last time you did a water change, previous to this one?

4 GSP's in a 120 liter tank is very, very overcrowded. If I'm remembering correctly, that's only about 40 gallons, which is big enough for one full grown GSP. At nine months, your fish should be qute a bit larger, I'd begin to wonder if they are cramped and getting stunted, which can leave them very suceptable to stress related illness among other things. I apologize if I'm wrong on the liters to gallons conversion though!

Hi Myaj

yes you are right is 40 gallons and was misinformed by my friendly LFS, he said i could have up to 6 in that tank!!

nitrate and nitrite <0.3mg/liter

previously did water change 3 weeks ago

While nitrate that low is OK, you don't want ANY nitrite reading. I think you need to up your water changes (weekly) doing 25-50% in the future each week. I'd suggest doing another water change right away and perhaps another a few days later...you need to get that tank nice and clean and keep it that way.

Do you have your own testing kits? They're worth the cost and will help you know when your nitrite is back down to zero.

Yes, you should be reading zero nitrites and ammonia, and as low as possible nitrates.

What probably happened... since you didn't do a water change for 3 weeks and your tank is overcrowded with very messy fish, the fish poo, uneaten food, etc has been sitting there rotting. This not only pollutes the water, but causes some chemical changes. When you then did a water change, you added water of such a different chemistry it was a heck of a shock to the fish, which are probably already stressed from being in such a small tank for so long.

What to do, do lots of smaller water changes, say 10% every day for a week to get your water back to "normal". After that you can probably go back to doing them weekly, but you are going to have to think about what you need to do to keep the fish alive, they can't last long in a tank that small. Either a larger tank or only keeping one of the puffers are your best options, and in the mean time, you'll have to keep the water quality under control by doing those water changes.