Diamond tetra or penguin fish?

[WinterWind]

I have a ten gallon which I can stock with a few more fish. Right now, it has a few cories and a male betta. I recently went to the LFS, and looked at what fish I might be able to stock my tank with. I wanted to get a small grouping fish. I saw diamond and penguin tetras, and both looked interesting. I would love to get one of these fish. I looked online, and the sites say they grow up to a maximum of 2.5 inches. I might get a group of 4 or so. Is this enough? What do I need to know about them? Also, I do about 50 percent water change weekly so I don't think overstocking is an issue. Thanks for your suggestions.

 

[SnakeIce]

from what I have observed and heard about the penguin tetras a ten gallon might not be enough room for a group of them because they are just a little agressive towards each other. It could be done, it just wouldn't be the least stressful situation for them and stress eventually means shortened lifespan.

I don't know what the diamond tetras temperments are like.