Fish all seem to prefer the corner of the 180g tank

[skitty]

I have a 180g planted tank with some tetras that all seem to gravitate to one corner. Why, and how can I get them to swim around more?

I reduced the amount of food and got a little more action, but still much the same behaviour as before.

The tank is a couple of months old and the tetras have all been there for 2 weeks to 1.5 months, and they haven't shown explicit signs of bad health.

Water parameters are approx
PH 7.3
Temp 25 degrees C, 77F
GH 6 degrees
Ammonia 0ppm
Nitrite 0ppm
Nitrate 5-10ppm
Lights 6-8 hrs / day
Filtration 2x big sunsun canisters
Food variety incl frozen blood worms, bug bites, vibra bites, frozen spirulina brine shimp, guppy flakes, and some inking foods.


The tetras are red phantom, silvertip, and congo, in schools of 6, 12, 6. There are some other fish (dwarf gourami, corys, guppies) but it's the tetras that hang in the corner.


I had a video showing this, but I'm not sure if it was preventing my post from showing up before...

 

[Caliban07]

I have a 180g planted tank with some tetras that all seem to gravitate to one corner. Why, and how can I get them to swim around more?



I reduced the amount of food and got a little more action, but still much the same behaviour as before.



The tank is a couple of months old and the tetras have all been there for 2 weeks to 1.5 months, and they haven't shown explicit signs of bad health.



Water parameters are approx

PH 7.3

Temp 25 degrees C, 77F

GH 6 degrees

Ammonia 0ppm

Nitrite 0ppm

Nitrate 5-10ppm

Lights 6-8 hrs / day

Filtration 2x big sunsun canisters

Food variety incl frozen blood worms, bug bites, vibra bites, frozen spirulina brine shimp, guppy flakes, and some inking foods.





The tetras are red phantom, silvertip, and congo, in schools of 6, 12, 6. There are some other fish (dwarf gourami, corys, guppies) but it's the tetras that hang in the corner.





I had a video showing this, but I'm not sure if it was preventing my post from showing up before...

Turn the filters off for 10 mins and see if they start swimming around. Might be too much flow.

 

[Brookster123]

Edited. Please stand by

 

[skitty]

update, they swim around when the lights are off...

I snuck up on the tank today when the tank and room lights were off and I took a "flash" photo on my phone... Lo and behold, the fish are all over the tank! I then turned the room (only) lights on and they all returned to the corner .

I tried turning the filters off and it didn't make an obvious difference. Maybe a bit more height used, but still in one area of the tank. I turned the filters down to 3/6 power and I'll let that go for a day or two to see what else happens.

 

[libertybelle]

Scared of the lights then. They still haven’t been in there long so they may come around but they’ll do better with more plants and cover to make them feel safe.

Surface plants also make a huge difference in convincing the fish to use the entire tank

 

[Lokilow]

Try more tetras, also get some cover for them to hide from the light. Overhangs or floating plants. Seems like the lights are just stressing them out and its not the flow.
With such a large tank you could fill it with more tetras so they feel safer exploring.

 

[skitty]

more plants?

Thanks for your replies. I will try more floating plants (and more tetras, eventually). As of now the hornwort all went to a maternity tank, but it will be back soon. The tank is heavily planted, but the plants are all pretty new in there and have yet to fill out and grow tall. Too bad my post kept dissappearing when I posted a video of the tank...