Stowaway gambusia devastating flag fish fry

[razornick]

One of the smartest additions to my koi pond has been American Flag Fish. They are a small native pup fish found in Florida swamps. Aquarium keepers know they are pretty close to being the best string algae eaters on the planet.

I inadvertently added gambusia to the pond via some water lettuce and frogbit. They are multiplying rapidly and they are difficult to catch. Within days, I could not see any of the recent Flag Fish hatchlings in the shallow perimeters. I have tried the soda bottle method with little result. I'm thinking of laying down netting in some of the shalow areas with strings attached to snatch up at a good moment?

Perhaps someone out there has a better method?

 

[DrDave]

I started with 12, in 2 years I had 1800. The only way is to drain the pond, sterilize everything, with bleach if neccessary, then wash and sterilize any plants before adding them back.

These fish are like pirranah and you cannot give them a break.

 

[razornick]

Yeah, I knew all along what you're saying is true. Only have had water in pond about 2 weeks and enjoying watching the biology come into balance. Breaks my heart to stop and start again. Thanks

 

[pondlady]

net out the adults as they will keep reproducing.
the little buggers don't care for salt. Gold fish like to eat the fry as well.
just keep at them. Maybe remove the flag fish for a while and add a few goldies. When the pests are gone remove the goldie and restart the flags??????????????

 

[razornick]

Thanks. I'm going to try laying black netting fabric tied by strings to a bamboo pole in a shallow area where they seem to congregate in early evening.

 

[DrDave]

You will never get them all that way. Remember, I started with 12 and had 1800 several years later.

 

[paradise]

ha ha , I started with 4 females, and now in my 2nd year, there are 1000s. I have given bucket fulls to friends and still it does not affect anything.

 

[razornick]

My pond is fairly new, less than three weeks with water. From what I can see, I have about 10 mosquito fish. From what you experienced folks are telling me, all attempts to get rid of them short of draining the pond are futile. The best I can hope for, I guess, is to try to control the population if I want the flag fish fry to ever survive. There were hundreds of tiny fry and now I don't see any. My pond is kind of like a doughnut with an island in the middle instead of a hole. This weekend, I am going to lay netting and try to chase them around the island until they get over netting area and then give them the yank.

 

[paradise]

You can get something that eats those small fish and release it into the pond. A big cichlid, if the water is warm enough can do it in a day or two, you wont have a single one left. See if a store will let you "rent" one. Red Devils in particular are very good hunters. Or Turtles.

 

[DrDave]

Unless you have no detail whatsover in your pond, no fish will ever get them all. How do you think they survive in the wild? They are fast, blend in and smart.

 

[paradise]

Dave, I have had Central American cichlids in a 200g tank with lots of decorations and rockwork get 2 dozen feeders (not goldfish but danios) in 24 hours, stalking and just knowing exactly how to do it. If he's only got 10-20 in there, 2-3 days and they are history. Next year I am planning to breed some cichlids in my tank. An experiment. We'll see how that goes with my 1000s of mosquito fish.

 

[DrCase]

i,m glad we dont have them here,,,god knows we got the skeeters

 

[pondlady]

Guess I am lucky, because I had 12 this spring and now I have 7. No fry that I could see all summer. No clue why. Have blunt nose minnows in there as well, Food for them maybe ?. The minnows do a better job with the skeeters as the little mosquito fish. They also eat at the algae on the pong sides. Rosy reds are the same minnow in a different color. They winter over here in Utah outside.

 

[razornick]

UPDATE... I don't want to be like Bush and proclaim a premature "mission accomplished," but I've had initial success using my netting idea. I caught 15 gambusia including three very fat and pregnant females. I couldn't see another mosquito fish after several checks early yesterday evening. About 40 percent of my pond is covered with floating plants so there may be some that simply don't venture into open water. But I figure if there are not enough for me to see then the population is acceptable. It only took me 5 minutes yesterday morning to get rid of what I could see. I was willing to repeat the method several times but only had to do it three times. The gambusia either can't see the netting or think it is debris in the water. They don't even seem to notice as it is being pulled up until the last minute. The trick is not to let them see YOU. My rig is a yard and a half of black netting material from Walmart (.79/yd), 50lb test fishing line and a long bamboo stick. Tie 3-4 feet of fishing line to each corner of the fabric then tie/knot the other end of the line together (think upside-down parachute). Tie this to the end of bamboo pole that is long enough for the gambusia not to see you at the other end. Lay down the netting in a shallow area where you normally see Gambusia foraging. Push it down with a stick and drop a few tiny peices of gravel on top to weight down the edges. Prop the bamboo pole over (not in) the water. Come back a few minutes later and slowly lift bamboo pole. The second and third time around I actually chased the Gambusia over the netting. They thought they were hiding. Anyway, I may post back in a couple of days that I jumped the gun on saying this was 100 percent successful. We'll see.

 

[elroyjetsn]

Wasn't aware of the problem with these fish! Haven't seed any mosquito larvae either. The ruby reds should handle that??

Is there a safe predator to keep in a pond for balancing the Ruby Red population without wiping out all the fry. The channel cats may pick off some of the bottom feeding fry but leave the other be. Of course we will be dining on the cats when they get big enough.:icon_smile: