well I'd suggest all three of you do a little more reading from the real experts like Dr Axelrod and get a little more experience.
Haplover, perhaps you need to update your library. Axelrod is out of date and at times inaccurate. The Baensch Aquarium Atlas series is a superior source of information. I suggest you read these reader reviews of Axelrod's opus. I have read his large atlas, and it did not live up to my expectations. I am currently reading Volume 3 of Baensch.
http
/www.amazon.com/gp/product/079380033...glance&n=283155
I have kept fish for 17 years and I would not keep neons with a betta. I keep harlequin rasboras with bettas, since they live together in the same biotope and complement each other well. They are also less nippy than tetras. Besides that, neon tetras do far better in mature tanks and I would never put them in a new tank. Of course there are exceptions to any rule and perhaps you have kept them well together, but that has not been my experience.
Drs. Foster & Smith are also not the be all and end all of Aquarium keeping.
Sorry about that Kairi, now to address your question. I wouldn't keep danios in anything smaller than a 20g. They are just too active. I kept my zebras, when I had them like 10 years ago in a 29g and they looked crowded to me, active little buggers.
Your 75 gallon stocking seems fine to me. Your 10g is better served with the betta and a small school of harlequins, like 6-7 would be great and a little more accurate than tetras or danios. Now what to do with your poor molly? This is when I say invest in a ghetto 5g hospital tank, where she can recover in peace. But she may be alright if the 75g is well-planted and there are plenty of spaces to hide. That decision is up to you really. She will be more comfortable with her own kind, and she might not be picked on as much once your tetra stocking is at optimum levels. When tetras are in an adaquate sized school, over 6, they tend to become more involved in their own group and will tend to leave other fish alone. Hope this helped a little bit.
