fish for 30g cube

[Delphinus]

I'm not sure what the recommendations are for tank sizes for the pygmy angels. To be honest, for me, a 30g would be pushing the limits on the small size for one of those, although certainly could be done for a while if you got a small one (and then had a plan to give her a bigger home when she gets bigger), but, it sucks to have to give up fish. Check the recommendations, other people might know it better than me, but like I said, for me I think a 30g would be on the small side.

Small tank fish that come to mind: bicolor blenny, orchid dottyback, various gobies, royal gramma basslet, a blue assessor ...

I think I've seen Firefish recommended for tanks in the 30g range but they too are jumpers, so a non-lid tank is a no-no for firefish IMO.

These are just suggestions "off the top of my head", you should double-check that 30g is within the recommendations for tanksizes for these.