65 Litre tank - 24 hour deaths

[Narghile]

Hi all.

In my tank I have 4 neon tetras, 4 other tetras and a siemese fighting fish. But anything else we add, will start dying in 24 hours. We have lost 3 X golden suckers, 2 X Bristol Nose, 4 X different types of shark & 4 X very vibrant orange fish and more.

25c water, most test come up with pH about 7, ammonia very close to 0ppm, nitrate around 2.5pp. & nitrite under 0.25ppm.

Local shop has test water and said the water is fine. What could be wrong?

Cheers

 

[JohnnyHyde]

Can you post pics of your tank? What else is inside? Plants, rocks, wood, etc...
Maybe there're not enough hiding places and betta harass them to death? What other equipment you have there? Temperature? Filter/heater works correctly?

Also, I think you're more less full with those 9 fishes... you can think of Bristle noses, but sharks (probably red tail sharks?) are way too big.

 

[Gourami Swami]

The tank is not fully cycled, it does not have the proper bacterial colonies established to convert ammonia into nitrite and then into nitrate. A cycled tank will read 0 ammonia, 0 nitrite, and nitrate rises until you do water changes weekly to remove them. Should stay under 20ppm. Any ammonia or nitrite levels, are quite toxic to fish.
Also, yes for a 65 liter tank, the bristlenoses and sharks would have been too large.
I would not listen to the guys at that pet shop, they don't know what they are talking about if they tell you that any nitrite reading is normal. Also, selling you plecos and sharks for a 65l tank, was not good.

Read up on this, it is the bread and butter of keeping fish alive in tanks:
https://users.cs.duke.edu/~narten/faq/cycling.html

 

[duanes]

Agree with everything Gourami Swami said.
Tank is "not" yet cycled.
This is a tiny tank, a mere puddle, soI wouldn't add any more fish, the tetras and Betta are enough.
You should be removing about half the tanks water every day and replacing it with dechlorinated tap water, to dilute the toxic nitrite. Your first fish (tetras, and Betta) have built up a slight tolerance for the nitrite, any new fish don't have the tolerance, and are dying from the nitrite shock.