What's up with this fish

[akshayj]

I have 6 Glofish Tetras and one of them does not eat, does not move much and overall looks very depressed.

When I go to feed the fishes, all of them get very excited and come to the top of fish, except this one which seems to be in his own world. See the below video.

https://www.veed.io/view/25429771-59b1-49a8-9940-947219b65e49?panel=share

Some pics:
https://postimg.cc/gallery/FfWs1nT

 

[Aiken Drum]

Please take a read through the "unhealthy fish" sticky and answer all the questions as fully as you are able. If you dont know the answer, say "i dont know".

https://www.aquariumadvice.com/forums/f17/before-posting-about-unhealthy-fish-read-this-32451.html

 

[akshayj]

1~What type of fish is afflicted? In addition, please describe what is wrong with the fish to the best of your ability (i.e. cotton like growth, bloated, etc.).
Glofish Tetra
Not eating, depressed and does not swim much.
See the below video.
https://www.veed.io/view/25429771-59...49?panel=share
Some pics:
https://postimg.cc/gallery/FfWs1nT

2~What are your tank parameters (ammonia, nitrites, nitrates, temp, pH)? Please give exact values.
I don't know

3~ How large is the tank? How long has the tank been set up?
50 litres
1.5 month back

4~What type of filtration are you using? Please give the name and number (i.e. Fluval 304) and amount of gph if known.
Blue Pet Aquarium Internal Liquid Filter BL-600F Suitable for 20-30 Litre Aquarium Fish Tank (Power: 6W, Flow MAX: 500 L/H)

5~How many fish are in the tank? What kinds of fish are they and what are their current sizes?
6 Glofish Tetra
6 Serpae Tetras
4 Common Mollies
1 Ballon Molly
3 Zebra Danios

6~When is the last time you did a water change and vacuum the gravel? How often do you do this? How much water do you remove at a time?
I change 50% water every week. I clean all the dirt during water change.


7~How long have you had the fish? If the fish is new, how did you acclimate it/them?
45 days
I dipped the plastic bag for 30 mins before adding in tank


8~Have you added anything new to the tank--decor, new dechlorinator, new substrate, etc.?
Nothing new added

9~What kind of food have you been feeding your fish, have you changed their diet recently?
Diet not changed
Feeding the flakes: Aquatic Remedies Gene Eleven Slow Sinking Micro Pellets, 100G for Tetra, Guppy, Barb and Betta Feed | 0.6 mm, 46% Protein

 

[Aiken Drum]

You are overstocked to a significant degree. Your filter is insufficient for the size of your tank, and more so for the high number of fish you have. On top of that as you dont know your water parameters, so you may not be cycled which compounds the problem. Id go as far as to say with that many fish, in that size tank, with such a small filter, it may be impossible to cycle the tank.

This will all be causing water quality issues and stress which will lead to a very poor living environment, and ill health. None of this can be fixed without improving the living environment, and the issues will be long term for these fish and may not be able to be fixed.

Short term, increase the 50% water changes to daily. And do not get any more fish.

Longer term you need a water test kit that tests for pH, ammonia, nitrite and nitrate so we can assess what the level of problem you have and cycle the tank. API freshwater master test kit is a good one to go for. You need to either reduce the number of fish in the tank by half and get a bigger filter, or get an aquarium at least twice the size (preferably 3x) with a filter rated for at least the size of the bigger aquarium to keep that number of fish. Really all the fish you have need bigger than a 50 litre aquarium even with reduced numbers.

 

[akshayj]

How many fishes are suitable for my tank?

 

[Aiken Drum]

Most tetras need to be in 80 litres to support a sufficient group size and give them enough room to swim about while not be overcrowded and stressed. Same for zebra danios really. Mollys really want to be in a 120 litre tank, but could live on 80 as long as it isnt overcrowded by other fish.

So with regards to the fish you already have, none of them should be in a 50 litre tank. You might get away with 6 glofish tetras or the 6 serpae tetras, but it will be poor quality of life and survive rather than thrive. If you cant get them a suitably sized aquarium they really need to be rehomed or returned to the store. The store have been very negligent selling you fish without making sure you can properly care for them.

There are fish that can live comfortably in your 50 litre tank though. You could get a betta, and it might tolerate company, in which case 6 small fish like celestial pearl danios or harlequin rasboras might go together. A guppy tank would work, so maybe 8 guppies. Small gourami, like a honey gourami could live in 50 litres, with maybe 6 of the previously mentioned danios, rasboras or guppies.

While 1" of fish per gallon of water is a flawed metric, when you are considering groups of small narrow bodied fish it will stop you overstocking. So 50 litres is roughly 13 gallons. So 13" of fish. By my reckoning you have 40" of fish when you are taking account of adult size, so they need a 160 litres/ 40 gallons. You do need to take account of minimum tank size too, so a zebra danio for instance needs 80 litres/ 20 gallons as a minimum and could support 10 of those fish.

You also have to consider your undersized filter which is only rated for about half your aquarium size, so really you should half the number of fish the tank can accommodate. So your tank as it is currently set up, could probably accommodate 4 small fish, that arent too active and doesn't need much room, so 4 guppies.