Hi there, you sound as though you live in the UK
I'd be worried about any nasty chemicals the 'insects' may pick up on their travels. Floor polish, 'Cilit Bang', etc... The nasty chemicals may build up over time in your puffs system.
I only feed my puffs on earthworms from my pond filter and arthropods (like woodlice but live in my pond). Just avoiding any pesticides that may be around. I do feed stuff from the beach, shrimps, crabs and anything else I can find.
I suppose being ten miles from a nuke power station, they may be slighty 'hot'
Wondered why my disc tetra is well over a foot long?! Sorry, Pacu joke
If you are near an angling shop, see what they have. It's normally very cheap. Also try a wet fishmonger's. You'd be amazed what they can get for you at almost no cost at all. The family run one here that I use recently supplied herring eyes for a university research project. I get my crab legs from them for £2 per half carrier bag full.
GSP's wil eat frozen blood worm when tiny but you have to be a bit careful of their teeth overgrowing and these need enriching with vitamins - 'Vita Chem' which you can actually get over here on the 'net. I use mussells from Sainsbury's to keep teeth in check but cockles in the shell are probably a better option. No vitamin C sucking enzyme in those
Please let us know if you have any more q's
Lastly, please persuade someone to get you a 250W metal halide light unit. It'll stave off the basement blues, especially if you hang it over a marine tank. Thoses things are serious mood enhancers
