I'm going on holiday next Monday and coming back Friday. I dont have anyone to come and feed the fish. I was wondering whether I could put a holiday feeding block in both my tanks and they would be fine? I have a variety of fish but if I fed them on the Sunday then could they survive until the Friday? I also have live plants and I know not to keep the lights on and I don't have a timer so is it OK if I kept the lights of the entire time? My large tank is 125l and has 2 pearl gourami, 6 harlequin rasbora, 6 black neons and a honey gourami. My other tank is 60l and has 5 cherry barbs, 9 neon tetra, 2 endler guppies and 5 corydoras (in there until I get back from my holiday then will be going in the larger tank).