I have a 29 gallon that is extremely over-filtered. I inherited guppies and cory cats. The cory cats are great, but the guppies are out of control. My number one plan is to control the guppies. I did make some new fish additions. I got 6 cherry barns, 6 glolight tetra, and 6 neons. All are beautiful and healthy. To manage the guppies, I got 10 ghost shrimp and 3 frogs. The shrimp are hard to find, but appear to be doing well. One frog is getting out there and eating with the cories. Another is a little skiddish, but is eating. I haven't seen the 3rd one much. The frogs and shrimp have seemed to chased the fry to the top of the tank. I have 2 German Blue Rams on order. I hope that will control my guppies. I will keep you all updated on my community.