Don't worry about it. Pet shops should tell you this, but unfortunately they are full of inept people that don't know what they're talking about and just want to get the tills ringing. I'm personally not a fan of flakes, messy and get everywhere. I buy Hikari stuff, small fish go nuts for their Micro Pellets. There's a massive choice but I'd definitely get some Tropical food. I have some for sale if you want it? Ha! I'm closing my tank down you seen and have allsorts of stuff to get rid of!I had 6 Glowlight Danios in a small tank, around 28 litres and they were fine. What danio is it?