All frozen food that is available for me here in UK I already have - I have daphnia, cyclops, bloodworms and a few other bits but all of those are small in comparison to let's say nerite snails I get. My loaches are active and curious so I don't see a problem with giving them an occasional clam or prawn to make their lives better, as long as it's not harmful. My LFS doesn't sell frozen clams but advised me that the store bought once cleaned and defrosted are good to be used as a treat I went with loaches knowing they will require different care but also I expected them to be more interesting for me to observe and in a way interact with. They come to the water surface when I feed them and if I put my hand into the tank when cleaning it they do swim close, sometimes even tickle me a bit with their barbells. My question about the clams was not dictated by me trying to get rid of my dinner leftovers, I am genuinely checking what is best for my fish and as 2 of them are now in need of the extra food / nutrients I might as well expand on their menu and see what works wellWhy not buy frozen food made for fish instead of humans? I can get frozen daphnia, bloodworms, shrimp, plankton; used to get frozen squid (this is highly nutritious and my fish really went after it) and frozen clam. I just did a search and frozen squid is produced by Hikari, San Francisco Bay, and Brine Shrimp Direct--all are fish food manufacturers in the USA so you may find one or more of these at a local fish store, or online.
Bloodworms whether frozen or fresh should not be fed more than once a week. I realize this is being eaten by the fish, but it is not nutritious nor healthy long-term, so it would be best to wean the loaches off this before it is too late. This actually applies to most worms.
My main fish tank gets all sorts of food rotated so I rarely feed the same thing more than 1-2 times per week (apart from algae wafers as I also need to provide those for the shrimps and snails).