Instruct: Classify the given Amazon review as either positive or negative.
Query: Fish love them, but they're an absolute mess.

These pellets are economical and fish do like them, but they have one HUGE drawback: they're filthy. In a matter of seconds in the tank they will begin to "puff up" and get soft, and start making a mess of your substrate. Even with the fish eating them, they can't keep it under control and just tend to create even more of a mess. These things will surely make a mess of your tank in no time if you don't clean up after your fish or if you don't under feed. If you are having any sort of health-oriented problem in your tank, from ammonia in the water to algae, one of the first things I'd do is stop feeding this stuff and start feeding a quality, clean food like any number of other pellets available by other companies.These are best avoided, only use them if you are in a pinch or to offer something different on a rare occasion for your fish. I'll never buy them again.