Hello, My family and I have a Juwel Rio 240l / 63 us gallon tank with 7 neon tetras, 6 panda cories, 5 male fancy guppies, 4 honey gouramis and 1 juvenile super red bristlenose pleco. In approximately 3 days, we're going to go on holiday for 19 days. We'll do a water change before we leave and a water test. We have a friend to check on the fish for us and to feed the pleco and panda cories the algae wafers and shrimp wafers every 2/3 days. As for the rest of the fish, we bought a Juwel auto-feeder which fits with our tank ( ). At first, we put very small pellets in the feeder but because they are so small, when we tested it, too many came out of the feeder. So instead, we bought some fish flakes and put them into the auto-feeder and when we tested it, a good amount came out efficiently. However, when we tested it again the next day, the flakes became stuck to the sides and all mushy similar to mushed tuna. I think it is because we didn't connect the air pump to it so overnight, it became mushy and stuck to the glass but I don't for sure. Any suggestions? Why do you think the flake food stuck to the glass? What other fish food should I try? Thank you and have a nice day!