Facebooking for advice, my OFAIL (that’s One Favorite Aunt In Law, not literally “O-FAIL”…I maybe should think up another acronym huh?) has a recently built, do-it-yourself fish pond at her rural home. And now she has, yup, the dreaded algae.
Sight unseen, I think she has two issues here. One is her new fish pond has algae and the other is her new fish pond gets algae. Algae needs but 2 things to grow: sunlight and nutrients.
There are two basic types of algae in fish ponds. String algae and plankton algae. Both make water a lovely shade of green if unchecked.
In no particular order and with random thought and commentary, let me offer up a couple suggestions on Ms. Shirley’s new fish pond looking like green split-pea soup (which is the plankton algae causing that).
- If your pond is in full sun…ohhhhh noooooo.
- Since algae thrives in sunlight, we gotta kill those bastard planktons, and Ms. Shirley, please know the chemical(s) you’re using now is fighting a losing battle. Shade the pond with a tarp or awning for now. This is an immediate and temporary way to discourage further algae growth and vigor.
- Quit feeding any fish in the pond. If they are not algae eaters, remove them and get out a fryer (just kidding on the fryer Shirley). If they are algae eaters, feeding them is like giving candy – stop it and they will go back to eating the algae.
- Algae is a result of excess nutrients in the water. Fish that are being feed will poop nutrient rich “bubbles-in-the-bathtub”, thus fertilizing and promoting more algae growth. Try to naturally balance the water nutrients (this might be more of a maintenance suggestion), letting the fish’s algae-digested poop keep further outbreaks in check.
- Stop feeding fish reason #2: if they don’t eat everything you feed them, the food will decompose and “release the Krackon” nutrients into the water.
- Remove any dead foliage or organic debris. Their decomposition in the water can also release chocolate-covered algae nutrients.
- Give a try to suspending a bag of straw in the water (in the current or at the waterfall) to remove some of the algae. Reportedly, Barley straw is best for this method. Be it known, this will not be an immediate solution.
- Filtration will be really, really important…oh boy is it important…oh so important. Your small pond shouldn’t require too big a filter, but you need one nonetheless, and then you need to service it regularly. Carbon filters are good for primarily filtering water chemicals, like chlorine; cartridge filters screen suspended solids.
- If you cannot physically relocate your pond to a more shady area, then consider installing an in-line UV filter. The UV light, as water passes by, will kill algae.
- Stocking your fish pond with the correct mouth-gappers is important. First to come to mind with fish for fish ponds are Koi. Koi will eat algae and keep it controlled. Unfortunately, your pond is probably too small for Koi – you might be able to have 1, but not for long.
- Ideally you want to “turn over” the water in the pond in 1-3 hours…meaning theorically every drop of water gets filtered in that amount of time. The filtration system or waterfall should not create a flushing toilet bowl effect. If it does, throttle down the flow (if you can) or give the swimmers (fish) a place to get out of the current, i.e. a rocky alcove or something.
- The “Microbe” you’ve been given…that is actually considered a “beneficial bacteria” and is good for water quality maintenance and once you get the algae problem under control. If you’re thinking it will do the trick in ridding your pond of an algae problem, it will but by the time it does, the pond will be frozen solid for the winter (and you for sure won’t need it then)
- Water plants – use them, especially if your pond is (and staying) in full sun. Water plants will shade the water and discourage algae growth naturally (starving them of 1 of the 2 things they need – sunlight)
- Fight the urge to over-stock your pond with fish. The fewer the better, and the filter(s) will be more effective. Looking at your Facebook photo of the new pond, I’m guessing no more than 2 big fish should populate the new Atlantis. However your pond supplier of fish might be able to help more. It really depends on the size of filter you have/use. The rule of thumb I suggest is for each 3 square feet of water surface, give a 12″ sized fish (pan size, right?) a home. If you have 6″ sized fish, then the population can double. Remember, as property manager of the fish pond, discourage casual mating practices (don’t ask me how) and use any over-populations as bait. Less fish is more (better).
- Consider the fishy populations: Tadpoles! Believe it or not, they can be good algae-eaters; Koi, as mentioned above, but they don’t always play well with others; bullheads and catfish…in cultivating the bounty for a fall fish fry of catfish, they will eat algae; snails do good with algae but keep in mind their pace eating is comparable to their pace moving about the cabin; goldfish – these guys might be your best bet; grass carp-not! they prefer a diet of foliage like pond weed and the like.
- There are many tropical fish that will eat algae. Consider them even though re-stocking might be an annual event (Hey! Why don’t you make it a celebration…invite the family!)
- In selecting fish for the pond, remember 3 major things: how big they get, will they eat each other, and can they survive a winter.
- An old-time remedy was to throw a piece of copper pipe in the pond to control algae. Well…this may work on the algae alright, but it will most likely kill off desireable water plants and poison the fish. Don’t do this unless you just want hydrology without biology.
- best advice is to limit the fish population, shade the fountain, cover much of the water surface with water plants, and whatever you do (or don’t) don’t skimp on the filtration.
Ms. Shirley, there are a number of algae control and fish pond management strategies out there. You will get people that swear they work, and other that just swear (when they don’t). I’ve just given you another strategy to try.
Please don’t swear at me if any of these suggestions do not work. If they do, can I have a dozen home-made cinnamon rolls?
Good luck Shirley, my OFAIL.