I would not keep them in a ten gallon - they get too large at more than 2 inches long. I wouldn't have them in less than a 20 gallons (76 litre).

If you plan to keep them with a betta, I would not have less than 8 in the school, as in smaller groups they are likely to exhibit fin-nipping behaviour. Definitely not three - that's just not enough for any kind of tetra.

 

Interesting.. would you happen to know how fast they grow and what size they start at?
It's possible that I could upgrade to a 20 galleon after a year or so (once I find one that isn't about to freak my real estate agent out too much).

Part of the reason I'm curious about them is that they're supposed to be very peaceful for tetras and I dislike Neon's because I had a bad experience with them as a kid. Glowlight's are looking to be my backup plan if Diamonds are no good.

I was aiming for 5-6 tetras which seemed like a good number to 'chill' them out but worried about overloading the 55L tank. I'm worried that 8 is too many even when they are young and under 2 inches?

My first Betta fish died last night actually, I wasn't 100% sure on Betta's but I loved his personality.. you're signature is way too true. Regardless of what I get I'm going to have to include a new Betta.

 

That's sad about your betta!

Have you considered ember tetras? They are very pretty and completely non-nippy. They are also slow swimmers, so their movement won't stress out a betta, and way too tiny for a betta to bother harassing. Glowlights are very similar to neons in temperament. You could easily have 8 in a 55 litre with a betta. They show their best colours in a planted tank and need soft water with a neutral or acidic pH (like all tetras). I have them and love them.

Diamonds are like any tetra - likely to nip if they aren't in a big enough group. I wouldn't do it in something as small as a 55 litre, because as you said, bioload issues, plus, larger tetras like more room to swim than the smaller ones. They reach full maturity at around 6 months, (I think), so they grow at much the same rate as most tetras.

 

Ember tetras would be better. As said before, you can keep 8-10 in a 10 gallon tank and they are completely non-nippy.

 

So I've been scraping the net trying to find out if Bettas and Diamond Tetra's are compatible and if they would get on happily on a fully cycled 55L planted tank.







Some sites say 10 galleons are enough but others say 20 at least and only one mentions that Diamonds and Betta's are compatible.







None of the pet shops around here sell Diamond Tetra's but one is willing to order them direct from the breeder for me if I want them.







My dream setup would be 1 better, maybe 3-6 Diamonds and a couple of shrimp if it's not overloading the system.







I'm fishless for the moment but any ideas would be most appreciated.

REPLY;
I have an 80L tank with a betta, shrimp, 10 neons and 6 diamonds. Since putting the diamonds in, both the neons and diamonds nip my bettas fins. So angry!!!
I was like you and couldn't find information on their compatibility. I asked in the aquarium I purchased them from and they said they'd be fine. They're not.

 

Diamond tetras like most tetras can be pretty nippy, you may not want to put them with a long finned betta.