Sunday, May 24, 2009

How You – Yes YOU - Can Raise Tropical Fish in Your Backyard

In North America, this is a great time of year to breed some types of tropical fish in your backyard (or on a balcony for you apartment dwellers.).

It’s fun and educational and – if you do things properly – you might even be able to make a couple of bucks in the process.

You’ll need a large bucket, tub or similar water-tight container, a proper spot to place it, water, gravel and the right kind of livestock.

Anything that will hold at least 10 gallons of water and is non-toxic will do. Rubbermaid makes 10 gal. plastic utility buckets and larger utility tubs that work well.

I use Rubbermaid’s model 4226 utility tub. It holds over 20 gallons.

You want the tub to get some filtered sunlight every day so that the plants will grow but not so much sun so that the water overheats. Placing the container under/next to a bush will filter the sun for part of the day. However, you may then have to deal with leaves falling into the tub.

You can try placing the container near a fence that allows light to reach the tub early or late in the day, but shields it from direct light during the most intense periods.

Standing water will attract insects, including mosquitoes. The fish I’ll recommend eat mosquito larvae. So, you’ll need to balance any concerns you have about mosquitoes and the live food source they provide the fish.

At night, when mosquitoes are most active, I place a wooden frame with window screening stapled over the frame on top of the tub. This keeps out the mosquitoes and the leaves. It also prevents fish from leaping out of the container.* Depending on where you live, you may have animals that come around at night and try to go fishing in your container. Placing a brick or two on the edges of the screen frame at night should keep them out.

Most of the fish recommend below are fairly hardy and will tolerate a wide range of water conditions.

From your local aquarium or pet store, you’ll want to get a floating thermometer, tap water conditioner (neutralizes chlorine, chloramines, and heavy metals) and a freshwater pH test kit. While you’re there, get some food for your pisceans - high-quality flake food and some frozen brine shrimp. Keep the latter in your freezer and only defrost the amount needed when feeding the fish.

Tap water should be fine to use as long as it is not particularly hard. The pH should be neutral (7.0) or slightly acidic (6.6 to 6.9) If the tap water pH is low or high, the store should have liquid or powder products that will adjust the pH.

Don’t fill the container to the top – leave about four inches between the top of the container and the water’s surface. This will reduce the number of “jumpers” leaving the container and will help reduce losses due to nocturnal predators (cats, raccoons, opossum, etc.). Remember to take this reduction in water volume in mind when measuring additives like water conditioners and pH adjusters.

Though not necessary, you can also add Tetra’s Blackwater Extract. Many tropical fish come from soft water areas that have a brownish tint to them - almost like a very weak tea. This color is primarily due to plant tannins dissolved in the water. The Blackwater Extract helps mimic that environment.* *

Even though we are setting up a freshwater environment, we’ll want to add a bit of un-iodized salt to the water. This will replicate the low levels of salt that naturally occur in many natural freshwater ecosystems and will also help keep disease pathogens in check. Add one tablespoon of un-iodized salt for every five gallons of water in the container.

Make sure you set up the container with the water and plants a week before you plan to add fish. This will allow for the water chemistry to stabilize. You should check the temperature of the water several times throughout each day to make sure the sun isn’t overheating the container. It’s best to keep the water below 83˚ F. If needed, move the container to a shadier area to keep the temperature in check.

It’s possible to have no gravel in the container. This makes cleaning the container easier. However, I prefer to make the container’s environment as natural as possible. Most “natural” aquarium gravels will work. For the best plant growth, it’s best to use one that contains iron-rich laterite.

Unless you decide to use plants that require a deep substrate for their roots, you’ll only need a layer about 1” think on the bottom of the container.

You’ll want to get some floating plants with long roots that hang down. These plants will shade the water, helping keep the water from overheating during peak sun periods.

One good choice is water hyacinth, a popular floating pond plant from South America. One plant will soon multiply into many and cover the surface of the container. You may be able to harvest some of them and sell them back to the aquarium/pond store.

The long roots provide a place for egg-laying fish to spawn and provide cover for the fry (baby fish). The roots also help support microscopic life that the fry feed on.

Another good plant is water sprite. It can be planted in the substrate or left to float on the surface. When lest on the surface, the leaves become much broader and looks like a different species than the bottom-planted version.

A small clump of Java moss on the bottom of the container will provide cover and a feeling of security for the fish when they are deeper in the container.

The tub set up and ready for fish!

Not all species of tropical fish are hardy enough to take the weather and temperature swings of outdoor life during the warm weather months. Probably the easiest fish to keep and breed are the livebearers including guppies, mollies and swordtails.

Guppies come in a wide variety of colors and patterns. Males exhibit flamboyant coloring while females’ colors are muted.

However, some egg laying tropicals can also be bred and raised. Killifish (killies) get their name from the Dutch work “kil” which means “stream.” They are egg-laying tooth carps that are distributed around the globe. There are hundreds of species of killies - and many species have a number of subspecies or populations exhibiting great color variety.

Some killies lay their eggs in aquatic plants where the eggs hatch after a few weeks. Others are called annual species. This is because they live in bodies of water that are often temporary, drying up for part of the year. When the rainy season begins, eggs from the previous generation that have been sealed in the moist mud are stimulated to hatch. The fry grow and mature quickly and the adults then begin laying eggs in the mud to prepare for the next dry spell. Sometimes the waters do not completely dry up so the adults live on. However, they are genetically predisposed to mature fast and to not live more than a few years.

Killies are not often found for sale in aquarium stores. They are mostly bred and distributed by hobbyists through clubs. Fish and eggs are exchanged via mail.

With guppies and killies, be sure you have at least as many females and males. The males will drive the females hard during mating and if the ratio of male to female is imbalanced, the females will become exhausted and may die. This is another reason to have a lot of plants in the container. The plants provide hiding places for the females so they can rest between bouts of spawning. Ideally, you should try to obtain trios consisting of one male to two females.

One of my favorite killes is Fundulopanchax garderni - the “masaj” population in particular. Its coloring is fantastic.

Fundulopanchax garderni from Africa.

F. gardneri is not a true annual but their eggs can withstand a “dry” (moist) period. In fact, egg hatch rates for eggs that are stored in a sealed bag on some damp peat moss are higher than for those that are left in water.

Check out this article for details on breeding and raising this fish.

You can learn about killies in general online. One great resource is the American Killifish Association (AKA). You can order killies to be sent to you my mail form the AKA’s Fish & Egg listing.

Limit your stocking to about 1 fish per gallon. So, if you’re using a 10 gal. bucket wit 8 gallons of water in it, do not add more than 8 fish. 6 would be even better and will allow a bit of room for the fry to grow.

Do not add any scavenger fish such as catfish or loaches to the container. They will probably eat the eggs.

Feed the fish twice a day. Most feedings should be frozen brine shrimp or blood worms. Don’t overfeed and pollute the water. At each feeding, the fish should be able to consume all of the food you give them within a few minutes.

Soon the fish will associate your presence with food and will come swarming to the top when you arrive to feed, or just admire, them.

If the plants are growing well, they will harbor small life forms that the fish will pick at between your feedings.

It’s a lot easier seeing and appreciating the colors and antics of the fish in a clear-sided aquarium. Since the buckets and tubs don’t allow for that, you’ll still have a beautiful top down view of them. If the diameter of the container is big enough, you can always put on a snorkeling mask or goggles and dunk your face in to get a better view – make sure you don’t have any sunscreen, makeup, hair product, etc. on you when you do so that you don’t pollute the water.

When fall approaches and the evenings bring the water temperature down to 70˚ F, it’s time to break down the container for the season. Odds are, you will have more fish than you began with and may be able to sell them to an aquarium store. The rarer and more desirable the species, the more valuable it will be to the store.

You can also set up a traditional aquarium in your home and place some of the fish there to continue enjoying them all year long.

If you try setting up one of these outdoor fish breeding containers, let me know how it works out for you.

*I’m not sure why but some species of fish love to jump out of their container. Most killifish can find even the smallest opening in a cover and leap through it.

** You can also make your own blackwater by soaking peat moss in clean water for about a week. However, you need to make sure that the peat is not from a gardening source (since chemicals may have been added to it) and that it’s clean. Some aquarium stores sell aquarium safe peat.


Unknown said...

Container fish keeping is great.
Great tips for setting up your first containers. I punch about 4-5 really small holes a few inches below the top of the container as a overflow outlet. For water changes I just fill the container close to the top and let the excess water drain out.

Last year as an experiment I grew out Peacock Gudgeons both inside and out. The outside Gudgeons grew much faster than the other ones. This year I plan on keeping some splash tetras outside. They jump out of the water to lay eggs on overhanging leaves, so I plan on keeping some young mangroves in the middle to keep jumping over the sides to a minimum.

I've dabbled in killifish a little - N'sukka, Bitaeniatum and striatum. I'm starting to get into them more due to a lot of great killifish resources in the Boston/RI area - Tony Pinto, Tony Terceira and Richard Pierce.

BTW - saw your announcement about the Dark Horse deal. Looking forward to the new Alien Legion series.

Rhode Island Tropical Fish Society (

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