Ch4rlie said:
The only suggestion I can think of that would be ok in a wide range of pH would be Threadfin Rainbowfish, Iriatherina werneri, they are good for pH range of 5.0 to 8.0.
http/www.seriouslyfish.com/species/iriatherina-werneri/
But I would certainly suggest you do a re-test of you water pH as suggested above from Daize and TLM and maybe gH and kH test as well if you have that or take to LFS and they might test that for you.
My LFS doesn't test with a reliable method unfortunately. I like threadfin rainbows a lot, but I'm concerned that they need larger tanks? I think SeriouslyFish suggests like a four-foot tank. If they would work well with my soft water, I wouldn't mind having them. They are quite beautiful.
Ah, then might be worth getting one of these API gH/kH test kit or any brand you prefer, even though you would rarely use it, its worth knowing exactly what you have from tap water, and it may be useful if issues arise.
That link IS from Seriously Fish, they suggest 60 x 30 cm tank being smallest considered which is basically a 15 US Gal size, I had Threadfins in a 90 litre / 23 US Gals tank, they were perfectly good in that tank.
But of course thats just a suggestion and an example of what would be suitable in your tank
not saying you MUST have Threadfins
Honestly I didn't even check the link, haha! I may be thinking about some other sort of rainbowfish.
So, right now, I'm thinking threadfins, chili rasboras (as well as espei and harlequin), or hatchetfish. I also like glowlight tetras (especially the albino strain
) and cardinals. Most of these are available at my closest LFS, but I can order any of them from the one further away.
Monday, when I get home, I'll check the pH in the bucket of water I left out, run to my LFS and get their pH for comparison, and see about getting an actual gh/kh result.
Would adding more plants help my pH situation at all, do we think? I was going to get a few new ones for the other two tanks. I'm happy with the plant population in the tank right now, but I don't mind adding more if it would help out.