Alternative Fish Foods

[SmallyBiggs]

I am interested in offering my fish an alternative diet. I've read that most fish will eat raw shrimp and clam meat, as well as green vegetables such as peas. However, I experimented with 1 littleneck clam that I chopped into chunks, and some frozen peas that I thawed in the microwave, and the fish didn't seem interested in either. I'm not sure if it is because I served it wrong, or because the particular fish I have simply won't eat these items. I have the following fish:
A siamese algae eater
A Blue Gourami
A pictus Catfish
3 Tiger Barbs
2 emerald Catfish

Should I try different seafoods/vegetables? Should serve it differently? Do they need to get used to this food? Or do the particular fish I have not go for these foods?

[Aeonflame]

I sometimes make a large batch of gel food and keep it stored in the freezer. You can add whatever you like to it and most fish seem to love it. Look online for recipes.