Too many fish for a 40g tank?

[7bubbles]

Hi all,

I currently have:
4 Platys
1 Swordtail
2 Mollys
4 Corydoras
5 Glass catfish
1 Apple snail
1 Siamese fighting fish

I would like to add some Cardinal Tetras (6 or 7) plus some Rummynose Tetras (6 or 7). Would that be too much? So far I have been doing 20% pwc and I test the water on a weekly basis indicating all levels are good.

What do you think? Would it be too many fish if I add the 14 tetras?

 

[adadkins1]

I would not add two schools of tetras. If I were you I would pick one species that I liked the best and stock 10 of them. 14 fish just seems like a lot considering they would inhabit the same level of the aquarium, but it might work out.

 

[7bubbles]

Would 5 Cardinals and 5 Rummynose be better than 10 of the same? Or 5 is too small for a school?

 

[adadkins1]

I would go with 10 of the same species. I know it is hard to decide on one, but if you get a larger school of the same species, the fish will thank you.

 

[7bubbles]

Cool, thanks for the advise. One last question: would the tetras be ok with the Betta (Siamese fighting fish)?

 

[Fishguy2727]

What is the nitrate concentration? It is impossible to determine how a tank is stocked without knowing the water quality. You may be overstocked now, or have room for 30+ more fish.

 

[7bubbles]

I test the water on a weekly basis and Nitrate has been constant at 40 for the last 9 weeks whe I started stocking the tank

 

[Fishguy2727]

What is the nitrate concentration of the tap water? The nitrate concentration should be below 20ppm before a water change, not 40ppm all the time. I think you need to figure out why it is so high before you even think about adding more fish that will only make it higher.

 

[7bubbles]

What is the nitrate concentration of the tap water?

That's a good question. I just re-tested the aquarium and the tap water. Results are pretty much the same: 40.

I use an API master kit (drops not strips) so I assume the results are accurate.

I live in the south east of England, where the water is quite hard and pH is constantly over 8. Maybe I should start a new thread on water conditions.