Am I overstocked

Is this tank overstocked? Have another tank to move things to if so.

55 gallon

6 XL Congo tetras
3 Juvenile Denison barbs
1 Pearl Gourami

15 cardinals
15 rummy nose
15 black neons

You are stocked to the limit imo.

With 30% water changes EVERY week, you're good, but you don't have much wiggle room if you get too busy.

Stocked at max. Nice tank btw.

I prefer to consider the question from another perspective. You are more inappropriately stocked rather than overstocked, though the first does lead to the second.

The real issue is the Denison Barb, species Sahyadria denisonii. This must have a group of 8 or more to be fair to the fish; reports of aggressive behaviour are likely due to the fish not being maintained in a sizeable group. It requires more water flow and cooler temperatures than the other fish (all of them) so it is not a good mix at all. And as it grows to 6 inches, a larger tank is needed. You may or may not have seen issues with these poor fish, but that does not mean they are not having them nor that you won't see them. The fish's genetics cannot be changed for our benefit.

Thanks for the replies everyone! I agree it is stocked to the max, if not, overstocked. I do 30-40 water changes every Friday without fail.

Regarding the denison barbs, they have yet to show any aggression towards each other/other fish, they group nicely, however it sounds like I should consider moving them to my other tank and increasing the numbers!

The congos are recent additions, and they are absolutely massive. I have owned them before but never seen them this fully grown before, so when I added them to the tank I was worried about everyone else’s space. Especially as I have nearly 50 other small tetras.

I will move the Denisons and am glad to hear everyone else seems like to will work

Oli said:

Thanks for the replies everyone! I agree it is stocked to the max, if not, overstocked. I do 30-40 water changes every Friday without fail.

Regarding the denison barbs, they have yet to show any aggression towards each other/other fish, they group nicely, however it sounds like I should consider moving them to my other tank and increasing the numbers!

The congos are recent additions, and they are absolutely massive. I have owned them before but never seen them this fully grown before, so when I added them to the tank I was worried about everyone else’s space. Especially as I have nearly 50 other small tetras.

I will move the Denisons and am glad to hear everyone else seems like to will work

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Yes on the denison. You maythink all is well, but we cannot talk to the fish so this is often a mistaken impression. Fish communicate by chemical signals, called pheromones (read by the species) and allomones (read by other species), and these can convey all sorts of stress and trouble unseen until it is too late.

That will give you room to increase the Congo, something else that will be in the best interests of that species. A group of ten to twelve here, you have space and believe me, they will reward you. Mine used to do relay races down the length of the tank, two males in turn, shimmering like glints of a rainbow. Floating plants will improve their colours too, they do not like overhead light.