The Puffer Forum

hi i have a tetraodon fluviatilis together with small fluviatilis and a small biocellatus and some other fish and yesterday i noticed that the big fluviatilis was extremely dark colored and was extremely unwilling to come out of his cave he sleeps in. he had no external features resembling any disease i haven't introduced anything new to the tank in months and the water parameters are all zero for nitrite and ammonia , i have one filter on each side of the aquarium for a total of two.

yesterday i tried changing water , did nothing. today i tried a salt bath and it did wonders for the big guy but now the small fluviatilis is in real bad shape with the same symptoms and i can see a kind of bulging in his stomach as is in the belly of the big guy, the biocellatus is thriving as normal and is cruising the tank as he always does but the small fluviatilis is as i said not recovering well, some of the symptoms resemble dropsy, but im not certain it could be internall parasites as well.

does anyone have any idea what it might be ?

ive attached a picture of the big guy when he was healthy

what is the salinity in the tank?
your larger fluviatillis needs a much higher salinity than the smaller fluvatillis and the biocellatus. What size tank are they all in?

PLEASE DO NOT TAKE YOUR PUFFER OUT OF THE WATER TO TAKE PICS OF IT!!! It's possible for it to ingest air, doing permanent damage to the fish, if it can't expel it.

Please read the Qs above, in red & answer more of them, so we can better diagnose the problem. Especially: tank size, nitrate, SG, water change schedule, feeding, etc.

hi thanks for the reply , i know of the salinity requirements for different species but i change the salinity most of the time mostly geared toward lower brackish and sometimes higher in between water changes , they dont mind concluding from their colours , so that could never be such a acute issue. the tank is 120 liter/30 gallon the big guy is 7 cm without the caudal fin which isnt that big but hes bigger than the rest so i call him big.

bye

OK what about water parameters (nitrates, SG), feeding info, water changes, how was the tank set up, how long?

Oh and what do you mean by:

arkose wrote:i change the salinity most of the time

Do you not have your salinity at a constant level, does it vary a lot or something?

i dont get it. if you know the salinity requirements for the different puffers, then you would surely know that the salinity requirements for the fluviatillis and the biocellatus are very different and would likely have a negative impact on your fish (which could be a reason why your puffer is black and unwell). Also, drastic changes in the salinity would surely crash your tank every week as your not meant to change it more than .002 each week.

Also, the tank is already overstocked with them fish which could be another reason why your puffer is ill

Agreed.. on all counts.

yep, i suspect your larger fluv is craving higher salt levels....

you said you have other fish in there, are they brackish as well...

hi the two fluviatilis are all better now whatever it was , it didnt last very long both fluviatilis are cruising throught the tank happily . i see some people are asking about the changes in salinity , maybe people dont know but these sea critters go from saltwater to freshwater in a matter of days so that a minor change in salinity can make them sick is complete nonsense and has no basis whatsoever, these are some generic answers which you could give to anyone there is no diagnosis no assessing the symptoms and from there there is no way to conclude such things, only when these critters are deprived of salt for extended periods of times only then will there be a negative effect on their health.

i hope this clears up some confusions.

bye

Its not that the changes in salinity make the fish sick, they can handle salinity changes just fine. We are well aware of that.

But the established bacteria/biofilter can NOT handle changes of more than .002 per week. Crashing your biofilter means there's nothing there to break down the ammonia/nitrites which WILL hurt your fish. If you are running a full saltwater system with a skimmer, this might not be as much of a worry, but any standard system that relies on a well established colony of bacteria is going to be in trouble if it recycles.

So don't just assume we don't know what we are talking about either .. we don't give out "generic" information.. we work with what we are given to work with.

love it when people ask for advice then insult the people who give up their time to try and help...

real nice of them.....

Exactly what myaj said, it's not necessarily the fish that can't handle the change but the bacteria, which then in turn harms the fish. Also, F8s can't handle the change in salinity as well as GSPs can. And I don't know how often you are changing the salinity levels but even the GSPs don't just nip back and forth between sw and fw whenever they like, they go for longer periods of time for certain things.

Sounds like they said what they had to say & has left the building...

Some people vary the salinity between water changes to mimic estuaries in the wild. As the tides ebb, the mixture of salt water to freshwater will vary on a daily basis. Maybe this is what the OP was refering to?

But, in an aquarium setting, maybe the fish do better in a consistent SG. What does everyone think?

Changing salinities is fine. Changing it more than .002 per week is not. If the OP IS changing their salinity more than .002 per week, that could very well harm the bio filter, which could be why his puffers were not looking healthy. Which is why we were warning him not to make big changes, as that could be part of the issue.

In the wild, fish swim through varying salinities no problem.. but the wild is not nearly as overstocked as any fish tank in the world (other than an empty one) and there's plenty of clean water to dilute ammonia down to pretty much zero, so crashing "biofilters" isn't an issue.

Usually the bacteria recovers relatively quickly from a minor salinity change, but it can do enough damage to a sensitive fish like a puffer in the time it takes to come back to a full quantity.