I just got 6 kuhlI loaches and one of them is missing. I noticed my canister filter intake seems to fit in kuhlI loach body size. I didnt know they were that small. But then again They sometimes burrow in sand and makes it hard to find them. What do you guys do to make sure they don't get sucked into the filter? I'm planning to cover it with sponge but wouldnt that reduce water flow?