Adding Extra Neon Tetras

Hi there,

Im new to this and I want to be cautious about overstocking my tank. I have a 17 US G tank with 5 guppies, a juvenile paradise fish (mis sold), 2 mollies, 4 neon tetras and a yoyo loach who I rarely see. My issue is that I'd ideally like to get a few more neon tetras as they do better in larger groups, but I'm worried I might be overstocked if I do. Would you recommend I get more? And if so, how many?

Thanks a lot

Welcome to TFF.

While you are correct that more neon tetras would be better for the four you already have, you are also correct to recognize the overstocking problem. A 17 gallon aquarium cannot house the fish you already have as they develop. I am afraid you have some serious issues.

Yo Yo Loach. You rarely see it because it is stressed. This is a shoaling species, meaning the fish lives in groups and this must be provided for in an aquarium. Loaches are also highly social fish; a group dfevelops an hierarchy, and there must be five minimum. However, this fish attains 4 inches, and it needs plenty of swimming space as they are (or should be) quite active fish, and they have an interesting interaction. Unless you have a 4-foot tank on hand, I suggest you return this fish or re-home it before it is too late. The stress these issues cause this fish weaken it and it gets worse the longer it continues.

Mollies are not small fish either, attaining 4-5 inches. They need moderately hard or harder water, contrary to some of the fish like the neons and loaches that require softer water. Water hardness is measured as the GH (general or total hardness). You can attain this info from your water authority if you are on municipal water. The mollies will soon out-grow this tank, but without knowing the GH we cannot recommend what you should consider.

The Paradise Fish is also soft water, but this fish has compatibility issues and this is going to be trouble before long.

I agree with the above. But captive breed fish can adapt to many different parameters.

Yoyo loaches can be ok in 36" tanks but 4' is better.

IMO the paradise fish could be just fine with neon tetras.

@Byron made an very good post. I agree 100% with him.

17 gallons is just not enough room for all the fish you do have. A 20 long would be better due to it's footprint but still there would be issues. Depending on the hardness of your water you could do just the guppies or just the mollies which would be for hard water or do your neon which would be soft water and add 2 more neon for a shoal. It is not the best situation but better than where your at now.

Thanks very much guys! I didn't knownthe yoyo and mollies got so big, I'll try and rehome them. I'm new to this and there's so much conflicting information out there that its difficult for me to choose the right amount of fish

The best place for research is https://www.seriouslyfish.com/knowledge-base/

The profiles in that site tell you how big a tank it needs; what water hardness it needs; what temperature it needs; whether it needs fast or slow flowing water; suitable tank mates and so on. Some profiles use inches, some use cm; some use ppm for hardness, some use dH. There is a calculator on here to convert them if you need to.


The first thing to do though is look on your water provider's website for your hardness (GH). You need a number and the unit of measurement rather than vague words.

I agree. SF is a great place to look up tank mates, tank sizes, water conditions, etc.

Thanks guys!

No problem!