Danio with positive flotation in new tank

[fkoran]

One of my danios is showing excessive buoyancy. It appears healthy and active, but slowly floats to the surface when it stops to rest. I noticed it this morning floating among some salvinia roots. The other danios are behaving normally. Here's a video of the fish floating: 

Here's a video of the healthy(?) danios:

Here's the history of the tank:

2021-12-12

Bought a 20 gallon tank, filled with water and gravel, added 6 stem plants and two bits of Salvinia, dosed the tank with two spurts of Easy Green. Started a sponge filter. The tank is lit with an 800 lumen bulb directly above the lid on a 12 hour photocycle.

2021-12-19

Added 6 danios to the tank along with a cup of Fritz Zyme 7. Danios surf the glass, eventually settle down in the darkest corner under some plants.

Added half a cube of frozen daphnia, this sank to the bottom, fish weren't interested in eating it.

Water parameters in the tank were as follows:

Nitrate    10 ppm
Nitrite    0 ppm
Hardness    300 ppm
Buffer    60 ppm
pH    7.6 ppm
Chlorine    0 ppm
Temperature    70 F

Water parameters in the store bag were as follows:

Nitrate    10 ppm
Nitrite    0 ppm
Hardness    0 ppm
Buffer    60 ppm
pH    6.4 ppm
Chlorine    0 ppm

The plants are generating new growth but there's no algae yet.

2021-12-20

After I turned down the light the danios emerged from the dark corner, patrolled the tank, grabbed some food from the top. I turned the light back up to get plants growing more quickly.

Dropped a few grains (like 6) of Xtreme nano, the fish didn't notice or aren't interested in eating it.

pH is down to 6.8, other parameters are stable.

2021-12-21

Dosed one spurt of Easy Green.

Water parameters are stable.

Dropped a few grains (like 6) of Xtreme nano, the fish didn't notice or aren't interested in eating it.

Fish continue to hang out behind the plant, occasionally patrol or chase each other.

2021-12-22

Thought I smelled ammonia but I don't have a test kit.

Water parameters are stable.

Fish continue to hang out behind the plant, occasionally patrol or chase each other.

Dropped a few grains (like 6) of Xtreme nano, the fish didn't notice or aren't interested in eating it.

Added a nerite snail to deal with any uneaten food.

2021-12-23

Dosed one spurt of Easy Green.

Water parameters are stable.

Fish continue to hang out behind the plant, occasionally patrol or chase each other.

Dropped a few grains (like 6) of Xtreme nano, the fish didn't notice or aren't interested in eating it (or are waiting 'till I leave?)

Nerite snail is slowly moving.

In the afternoon I found one fish floating among the Salvinia roots.

I moved the sick fish to another tank that I'd set up to grow plants more quickly. The new tank has a pre-set heater that's somewhat warmer than the main tank. The sick fish is darting about being distressed and floats the surface when it stops to rest.


I'm about to go out of town for a few days. What should I do to give the remaining fish the best chance of survival? I did a 50% water change in the main tank, added another splash of Zyme 7, and floated a black planter basket to give them more cover.
 

Edited December 24, 2021 by fkoran

[Colu]

I would recommend getting an ammonia test kit I would do another large water change and add a double dose of prime as it detoxify ammonia for up to 48hr I think you don't have enough cover I would add some floating plants such as water lettuce Amazonian frogbit some more plant such as vallisneria as it could be stress due to  lack of cover that's why there not coming out to eat the fish with the buoyancy problems it could be swim bladder or caused by a water quality without noing your  ammonia level it difficult one and what temperature are you keeping them at as some species of danios like it a bit warm yours look like danios nigrofasciatus the dawrf spotted danio like temperature of 75-83

[fkoran]

On 12/23/2021 at 6:19 PM, Colu said:

yours look like danios nigrofasciatus the dawrf spotted danio like temperature of 75-83

That's right, they were sold as dwarf spotted danio. The co op employee said they'd be fine at 70 F but I've noticed they get more active and bold when I turn up the temperature even slightly. Will set it to 24 C / 75 F while I'm out of town.

[fkoran]

Both the healthy and the sick fish are eating daphnia now after ~30 minutes of warmer water. 

[fkoran]

@ColuIs there a reference I can use to get the temperature requirements of different species? Is it a matter of acclimation? Some random googling brings me to this site, which reports 65-79 F for this species

https://www.seriouslyfish.com/species/brachydanio-nigrofasciatus/

[Colu]

It could have been the low temperature affecting there  appetite if they have started eating once the temperature has been turn up I would  just monitor the one with buoyancy problems if he's eating for a couple of days if you notice no improvement it could be swim bladder I would do Epsom salt baths 1 table spoon for 2 gallons for no more than 15 minutes 2-3 times a day as Epsom salt acts as a muscle relaxants to help relieve pressure on the swim bladder

[fkoran]

On 12/23/2021 at 7:17 PM, Colu said:

the one with buoyancy problem

Would you put him back in the main tank with the others if you'll be gone for a few days?

[Colu]

As long as he can compete for food and not going to get bullied you could put him back with the other as for reference material I have over a hundred books that what I use as you get a lot of contradictory information online depending on what site you look 

Edited December 24, 2021 by Colu

[fkoran]

2021-12-26

Sick danio is still alive. Floats under the sponge filter or under plant roots when resting but is able to pursue frozen daphnia in a group with the other fish at feeding time. Water conditions are stable

[Colu]

I would try the Epsom salt baths see if that has any effect