Zebra Danio Fat And Not Swimming

[ShaunM]

Hi. I'm a first time tank owner.

I have a fat, sick Zebra Danio not swimming about. I could tell she wanted to stay still so I switched off the motor for a few minutes, and she just just stayed still with her fat belly resting on the gravel.

I think she might be full of eggs but can't lay them.

I think it's a famale only because it's larger than my other danio.

The smaller Danio looks completely healthy and is still trying to play with the female, but is only making her more exhausted.

I don't think I've over fed them, in fact last feed, the female did not even eat. And the male looks quite slim.

The 35 litre tank is 3 weeks old, the two danios were added after one week, so I'm about two weeks into the cycling process. Up until yesterday both fish were happy and played constantly. I did my first water change yesterday because I detected some nitrate for the first time.

Any help appreciated. I have a feeling I'll find her upside down soon.

Tank size: 35 Litre
pH: 7.6 (I am bringing it down to 7.0 now)
ammonia: 0
nitrite: 5.0
nitrate: 0
kH: (whats that?)
gH: (wqhat's that?)
tank temp: 27C / 80F

thanks

 

[xJake]

Your tank is still cycling as you have a nitrite reading which is good, but also bad. All of the ammonia in the water has been turned into less toxic but extremely deadly nitrite which impairs gill function and suffocates the fish if too much is in the water. The fish are probably stressed out from the lack of respiration ability and this one developed an internal infection do to the poor water quality while cycling the tank. If he/she is sitting at the bottom and bloated the organs are already infected and probably severely damaged which means that he/she probably won't make it; even if you do treat him/her and kill the infection the organs will still be severely damaged. It would be good to euthanize the fish so it doesn't have to suffer any longer by putting a bunch of ice in a bucket of water and then dropping the fish in after a few minutes to kill it instantly. Cycling a tank with fish is very hard on the fish. Sorry for your loss.

Also, do an immediate 30-50% water change to lower the nitrites for the rest of the fish and then add some salt to block some of the nitrite from the gill tissue and improve gill function.

 

[ShaunM]

Thanks, she died last night. I did a small water change lats night and after reading your reply this morning I've just done a 50% change. The nitrite is now around 1.0-2.0.

The other danio seems to be o.k for now.

thanks

 

[WILDER]

Sorry rest in peace.
there is no gurantees that when using fish to cycle a tank they will make it, it takes it toll on them causing there immune system to shut down.

 

[xJake]

Keep up with the water changes until it's below 1.0 and add 1 tbsp of salt (sea, kosher, rock, aquarium; just not table salt) per 5 gallons to block some of the nitrite from the gill tissue and improve gill function. Also, asking around at your LFS's for mature filter media would help to speed along the process. If you don't have the time to do water changes you should pick up some Seachem Prime which will help to detoxify some of the nitrite. Another thing you can do is lower the temp a few degrees to increase the oxygen levels as danios don't need such warm waters and can live in waters as cool as 64F.