ALL fish will get caught up in suction if it is strong enough. I would let the minnows be, in the pond. What the SIMPLE solution is, is to put on a proper intake strainer that reduces suction by spreading it out over a large area. For example, on a 6" diameter intake pipe, put a 15"-20", (or larger diameter pipe) that is at least 20' long and/or "TEE'd, and has a 1/8" mesh stainless steel screen over it. If attached with flexible suction hose and in the right location, it would be easily cleaned with a garden hose.
Chances are high that the "minnow" is Gambusia. Gam's are live bearers just like guppies. They will thrive in the roots of your floating plant (I'm guessing Hyacinth's), and the gam's will keep the roots cleaner along with creating some nutrient for the plants.
A proper pre-strainer that has minimum suction will save a buttload of time and money from down time...relatively east you design, install, maintain, effective, and with one or two back up strainers to switch to, the least expensive solution, long term.
Find me a good Fab shop and materials, and I could you could have you clog free for several weeks at a time in just a few days... and for only a few grand. WAY less than rotenone, which is unlikely to kill all fish. Adding fish won't solve the minnow problem, because predator fish will need food, and even if adding enough predators, what do you do with the predators after minnows are gone? Catfish are out, because they eat plants, and so would most any fish, if starving to death.
Last edited by Rainman; 05/03/16 08:57 AM.
