Outdoor Tubbing Your Fish

OUTDOOR TUBBING YOUR FISH
By 2manyfish - March 12, 2003

Most aquarists have plenty of experience keeping indoor aquariums. This is the most common way to keep fish, and it works well. It allows total control over the environment in the tank, summer and winter.

However, not all fish do best in an indoor location. Some fish considered "difficult to spawn" suddenly become quite easy to keep if they are kept in tubs on the patio.

Such tubs don't have to be elaborate. There are some fancy kits consisting of a 1/2 oak barrel holding a plastic liner, and these make wonderful outdoor tubs for small fish. The liners usually contain 20-25 gallons of water. This makes for an ideal container for a few 2" - 3" sized fish. My personal experience has been mostly with various varieties of Australian and New Guinea Rainbowfish. These fish seem to really enjoy living outdoors, and spawn almost daily in tubs.

Tubs should be round, not rectangular. This is because a round tub is the most structurally sturdy shape to contain water. If you visit a local home garden store, you'll find some thick black tubs specifically made for patio fish containers. These tubs will give you years of service. If you get the oak barrel liners that lend structural support, they'll last indefinitely. I have several such tubs that are going on 6 years in service, and they show no signs of weakening. If you decide not to place the liners in containers, be sure to rest the tubs on a sheet of plywood or masonite. Don't rest the tub on concrete; it will be too difficult to maintain temperature stability if it's not resting on wood.

The tub should not be filled to the brim, lest fish jump to their deaths. Filling with about 20 gallons of water in a 25 gallon tub is about right. This leaves a lip of about 5" - 6" around the edge, preventing fish from leaping out. However, Goldfish will require even more of a safety distance! Shubunkins in particular seem prone to leap, and should be kept in containers no more than half full. Or, you can fabricate a screen cover to keep energetic leapers from committing suicide.

The floor of the tub can be any of almost any aquarium substrate, such as gravel or sand. However, I have had best luck at spawning egglayers by laying in a layer of river rock. This provides gaps through with any eggs may drop and be protected from being eaten. Males seem to have no difficulty fertilizing the dropped eggs, and hatches seem to be regular and often, frequently daily throughout the summer.

Most tubs are going to require some sort of air movement to maintain adequate oxygen levels in the water. Keep a close eye on your fish when you first add them. If you discover them at the surface of the water the next morning, gasping for air, it's a sure sign of low oxygen levels in the water. An airstone works well to keep the little pond churning and aerating day and night. Most air pumps can be placed outdoors near the pond. If you provide a little waterproof roof over the pump, it will give good, reliable service. Run a length of airline tubing to the airstone, and anchor the stone near the bottom of the tub. This will provide all the oxygen your fish need. This is most important in the heat of the summer. Remember, warm water holds less oxygen than cool water.

During the typical summer months, where temperatures remain above 80 degrees, the water temperature will slowly fluctuate up and down, but it should remain warm enough for most tropical fish. If your overnight temperatures start dropping down into the low 60s range, you'll probably want to provide a submerged heater, set to kick in if the water temperature drops below a certain point, say 75 degrees. For most outdoor tubs, a 200 watt heater is more than adequate to keep the temperature of the tub at a comfortable level, even if the outdoor air drops down into the high 30s or 40s. If your winters drop down into the freezing range, you'll probably want to remove the tub inhabitants and move them inside to their winter home. However, if you don't experience deep nighttime temperatures, you may discover that a 200-300 watt submerged heater allows you to keep your fish in their patio tubs all year round. You'll need to keep a close watch over water temperatures for the first year to see if this is possible in your area.

Water lilies provide welcome shade and protection for your tub inhabitants. These may be purchased at any fish store that carries pond supplies, such as most Petsmarts. Lilies come in small black plastic perforated baskets, and include all you need to grow beautiful flowers in your tub. Place the baskets so that the top of the plant bulb is positioned a few inches below the surface of the water. If the tub gets a few hours of sunlight every day, you'll quickly have beautiful water lilies spreading over the surface of your tub. These lily pads will provide a welcome hiding area under which your fish will congregate.

If you want to keep the fry you'll be getting, you'll want to float a layer of Hornwort in the tub. If you provide a layer about 4"-5" thick at the top, fry will naturally head for the surface and hide in the plant mesh. You'll be able to see them hiding in the plants. If you wish, you can net them out and move them indoors to be raised. However, there are some advantages to keeping them outdoors.

Outdoor tubs encourage plenty of microscopic growth. Daphnia, infusoria, all sorts of micro critters will quickly take up residence in your tub, providing a 24-hour buffet for fry. If you have a large number of fry, you'll probably want to supplement natural foods with freshly hatched brine shrimp. After the fry are a few weeks old, they'll appreciate finely powdered general purpose flake food.
Fish kept in outdoor tubs tend to be robust and healthy. There is something about a few hours of sunshine every day that helps them develop deep, rich colors not attainable in indoor aquariums. Boesemani Rainbowfish kept in outdoor tubs tend to have deep, brilliant colors just like the pictures you see in books and on websites.

About the only predators and parasites you'll need to watch out for are Dragonfly larvae. These can devour young fish at an alarming rate. If you see Dragonflies hovering over your tubs, you may want to stretch a screenwire over the surface, to prevent them from laying eggs. Mosquitos are usually not a problem; the fish will very quickly devour any larvae that may appear at the water's surface, again providing a nice, fresh meat dinner for the fish.

Be aware that some cities come around and spray insecticides on a regular basis. You really need to check with your city government and see if this might be happening (you might not even be aware that they're spraying). If they do spray, find out the schedule and cover the tubs with plastic sheeting while they spray. Some insecticides can kill fish very quickly.

Evaporation will be a constant problem, due to the water's exposure to air. Watch your water levels and keep the tubs at the level you have selected. You will also want to do an occasional water change, just as you would an indoor aquarium. This keeps the water fresh. Water lilies and other plants will almost certainly consume all the nitrates and other waste products, but you'll have a healthier tub if you do a 25% water change every week or two.

Outdoor tubbing is much easier than you think, and the fish will enjoy the adventure. Give it a try, particularly with egglayers. You'll probably discover they are much easier to spawn if kept in outdoor tubs.

(Editor's note: 2manyfish passed away on June 8, 2003. This was an article he wrote not long before his death. It is published in his memory. - RG)

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OUTDOOR TUBBING YOUR FISH By 2manyfish - March 12, 2003

OUTDOOR TUBBING YOUR FISH
By 2manyfish - March 12, 2003