years ago i struggled with unwanted pest attacking my fish. in the early days there was only one guy around to get pond supplies from[no internet] it took 2 years of study but i found out why,. myself like many others bring in plants to the pond. this is what i learned over the years. i almost gave up the sport.the plants lets talk the most plants that are common are the floaters, hyacinth, lettuce, i highly recommend the quarantine of these before they hit the pond.why ? because MOST are kept with fish.people dont care about your pond they care only about selling these. the truth is most carry these critters; LICE, ANCHOR WORMS, LEACHES, SNAILS. after struggling with this i finally got a book . then it all came together. my local fish, pond supplier was to blame and to this day he does the same thing.he brings in the hyacinth.... does not treat it he sells it as fast as he can. and stocks the store with countless chemicals to kill the bugs.LICE , ANCHOR WORMS. then one day i caught him doing this unloading the plants no treatment to kill them off resulting in my fish and everyone's fish getting lice.all floaters should be put in a container. regardless of where you buy.why? they have eggs on them..and in 21-31 days depending on water temps .. the eggs will hatch. then they attack the fish. you will notice the fish FLASHING. its being attacked.to stop this is simple. leave them in container and treat with dimilin x . a very safe way to stop them. its very hard to overdose, not expensive. treat 3-4 times..with water change.then after 30 days in the pond they go. i do use the stuff as a precaution and i add it to my pond every year.********WARNING**** there is a new bug out there ill bet .02 no one here has heard of before. i got hit with these 2 times in the last 3 years. so im gonna help you all out .they are called HOPPERS. a very small reddish looking bug thats is the size of a grain of coarse black pepper. THESE WILL KILL EVERY hyacinth in the pond. they will look like it got hit with a frost. the bugs .they hop..off the plants and hit the sides of my tubs. these were introduced by or government...to combat the plants in florida, texas, california. they introduced 3 strains from. down under, Africa, south America.if you buy off ebay; you better watch out. people there are hitting the drainage ditches collecting them from flordia etc.etc. and selling them cheap and spreading the bugs.. i have not found any way to stop them in warm water. they bore the eggs into the bulb. you cant detect them. even with a microscope. they multiply like a wild fire incredibly fast.they will kill every hyacinth.. the fish will eat them but they cant keep up...i recommend going to a supplier that has a green house that over winters them . still look close for them , i got hit last year doing this but the year before no issues, later found out a new shipment of other plants that required water boom they got hit. so people be extra careful. in all my years i have never been able over winter the stuff ive spent hundreds trying no success.im moving now to just lettuce. the fish seem not to eat it as bad as the hyacinth. i gotta have something for my fri..i choose lettuce now. snails if you have plants ill bet you got them, you have probably seen eggs sacks in the filter .snails are carriers of a host of diseases.. they eat your plants.so watch your source very close. leeches many different kinds if you got plants you probably have them. fish will control most. but there is one that does attack fish- humans. and yes it does happen.very easy to control. let the plant in question dry out NO water dry 100% 1 hour they are done.same with pond or filter 100% dry. they will crawl fast to any drop of water and survive.i hope this helps everyone. i know it will save you money and time, and it will for sure help the fish pond.. mike