Category Archives: Aquaria

Snails in an aquarium

There was a time when snails were thought to be necessary to have in a home aquarium. The idea was that the snail would clean up the fish droppings and the snail droppings were good for the plants. The plants in turn would give off oxygen that would help keep the fish healthy.

The reality is that the snails don’t eat the fish dropping, and the snail droppings add to the tank debris. Plants can utilize some of the droppings but the rest must be cleaned up by the filtration system. Plants do give off oxygen during the day, but the fish are not dependent upon that oxygen source if you have a good filter that is aerating the water.

The filtration system in the aquarium cleans up the animal matter and provides the necessary aeration to the fish tank. So what do snails do? They clean up excess fish food that would otherwise foul a tank. They help by eating some of the algae that adhere to the tank walls. They eat on the eggs of the fish, breaking them up but not consuming all of the egg before they move on to the next. Snails will also eat on the plants. Most of them usually do not eat the whole plant. They make holes in the plant, weakening them and disturbing the ambiance of the aquarium décor.

There are hundreds of snail species. The most common snails which are most likely to find their way into the aquarium as a stowaway on plants and live food is the Pond Snail. Most of them are prolific breeders. It is necessary to thin the snail population from time to time or they will consume the tank plants. The easiest way to thin the population is to crush them. Many fishes will eat the crushed snails and benefit from the live food.

Some fish breeders raise snails as a source of fish food. Not only will larger fish eat crushed snails, but the snails will help produce infusoria, a collection of tiny single-celled and multi-celled organisms that very small fish can eat. The Apple snails are a common group used to help start infusoria. The snails eat large quantities of plant material, such as lettuce. They produce a large amount digested waste that is a wonderful source of food for infusoria*.

*The use of infusoria was mentioned in an earlier posting.

Live bearing fish in a home aquarium

In several other posts we have looked at fish breeding. We learned about fish that scatter their eggs and fish that hide or anchor their eggs. Fish that harbor their young within their bodies are called livebearers. This group of fish sometimes harbors the eggs in the mouth of the parent and sometimes in the abdomen.

There are about 4 species and a couple of sub-species commonly that are used in a fish tank aquarium. Included in this group are Mouth-breeding Betta, Moffat’s, Gunther’s Cichlid, and Black-chinned Mouthbreeders. In this method of spawning, the female drops her eggs and they are fertilized by the male. Then the eggs are picked back up and kept by one of the parent fish in the mouth until they hatch. The mouth of the parent is not only an incubation chamber, but after the young hatch, a place of safety to dash into in case of danger. Watching the young dash for safety can remind one of people rushing into the New York subway during rush hour.

Many more species of common fish tank fish retain the eggs within their abdomen, and include more than 20 species and several subspecies. Some of the more common to a home aquarium are the Guppy, Molly, Swordtail and Platy. Some of these species will inter-breed in captivity. This knowledge has given amateur and professional breeders a field day in producing many variations in colors and bodies that would not occur in nature.

Animals that retain fertilized eggs within their abdomens are called ovoviviparous. Eggs are produced and then fertilized internally by the male as he swims along beside the female, and the fertilized eggs are carried within the abdomen until they hatch. (This is not the same situation as found in mammals. Mammals not only retain the eggs, but set up a nourishment system from the mother to the young through the placenta. Ovoviviparous species simply retain the eggs and do not provide a maternal nutrition source.). Additionally, in some species the female fish can retain sperm cells for many months and as many as 8 broods have been produced from a single insemination.

As a general rule a well-fed mother will not eat her young. This does not say that other fish in a community tank will not feed on the newborns.

Fries can be produced and survive in a community tank. However, if the expansion of your fish population is your goal, a properly setup breeding tank will give you better results.

Breeding fish in a home aquarium
Crustaceans and larvae as fish food
Fishing games—a sea of options
Fishing as a pastime for you and your family
More about egg-laying fish

More about egg-laying fish

By Rita:

In an earlier post I briefly described the most common egg-laying style of fish in a fish tank aquarium, egg scattering, and provided some insight as to why these eggs often did not reach adulthood. In this post I will discuss some of the other egg laying strategies. Each group is presented in order of parental attentiveness to the offspring.

The egg scatterers have no parental interest in the eggs or the fry. They are also likely to eat their own eggs after the spawn.

The egg hangers on the other hand are not as apt to eat their own eggs. The spawning fish lay and fertilize each egg then hang them by a fine, sticky thread from plants usually near the top of the aquarium. Beyond that there is no parental care. This group of fish includes Lyretail, Panchax, Lampeye, and Rivulus plus others. Most of this group is not common to the average tropical fish aquaria. One of the reasons is they are among the more expensive fish. The expense is due to the fact that it takes more time and space for breeding. The female will lay up to 200 eggs over a 20-day period. The young will then hatch in a staggered period according to the day laid. This can result in a hodgepodge of growing fry. The younger fry is in danger of being eaten by the earlier hatched larger fry.

Nest builders are the another group and they take a slightly more active parental role. The nest is first prepared either by sticking bubbles together or gluing aquarium debris into a nest. The eggs will be deposited into the nest. The nest is then protected until the eggs hatch. Once the fry hatch they are on their own. The fish that comprise this group are the Sticklebacks, Siamese Fighting-Fish and Gourami.

The most protective of their eggs and off spring is the egg hiders and the egg anchorers. This group consists mostly of Cichlids and Dwarf Cichlids. It also includes Angelfish, Jack Dempsey and a few others. As the group name implies the eggs are attached to a surface either secluded (the egg hiders) or in the open. Both partners concern themselves with preparation of the spawning bed, the care and protection of the eggs, and the care of the fry for a period of time after hatching.

To leave a pair of spawning fish in a community tank is always a risk. A properly prepared breeding tank would greatly increase the chances of having viable young.

Breeding fish in a home aquarium

The usual fish tank aquarium is set up for the enjoyment of the observer. An aquarist will often buy a pair of fish, a male and a female. As with other creatures when a male and a female get together the natural impulse is to breed. A natural question might be, ”Why doesn’t the aquarium soon over flow with fish?” One of the answers to such a question is related to the breeding needs of tropical fish.

In some cases, fishes in captivity do not acclimate to aquarium conditions. Even though they may be kept alive and in good health there is “something” missing. The missing element could be one thing or a combination of things. It might be that the water pressure is not right for that breed of fish to spawn. For some fish there is a need for a lot of surface water and even a large fish tank cannot provide enough surface water. Some fish are rendered sterile under normal shipping conditions. Not all the reasons are known and most are speculation.

For the fish that do breed in a fish tank aquarium, the usual community tank does not give enough protection for many of the fry to survive. This is especially true for the egg scatterers.

Egg scatterers comprise a large portion of the commonly used tropical fish population. Included in this group are the Tetras, Pencilfish, most of the Barbs, some of the Minnows, Hatchet, and Catfish as well as many others. The process is just as the name implies. The female swims and scatters her eggs; the male follows behind her and fertilizes them. An observer sees this behavior as a chase. Other fish in the tank see this as a feeding. Even the parent fish will enjoy the roe once the spawning is completed.

A few of the fertilized eggs may make it to the bottom of the tank and find shelter in the aquarium gravel. The eggs differ in degrees of stickiness to none at all. The sticky eggs may adhere to an aquarium ornament or plant; some of the eggs may float. All of the eggs in this group are abandoned by the parent fish making them susceptible to scavengers. Even the eggs that make it to the safety of aquarium sand or gravel have only a slight chance of maturing into fry. Bottom feeders and scavenger fish will eat most of them. If an egg should be able to hatch their chances of survival are next to nothing. The fry are non-swimmers until the yolk sac is absorbed and a lack of an appropriate food source will also inhibit the small fish’s chances of survival.

More about egg-laying fish
Live-bearing fish
Aquarium gravel and water
Aquarium stands, options and considerations

Diverse food for aquarium fish

In a previous post I touched lightly on the importance of giving aquarium fish live food. Live food provides a more natural and a more balanced diet than a commercially prepared fish food. The prepared foods should only be considered as a basic diet, not the total diet.

A typical way of feeding aquarium fish is to sprinkle a quantity of dry food into the aquarium. As the food slowly drifts to the bottom the fish try to get a share. If the fish are unable to eat all of the food, it settles into the aquarium gravel. Bottom feeders and smaller fishes will eat some of the settled food but if it is allowed to stay in the tank it will rot and foul even a large fish tank. Live food not only gives the fish more of the nutriments they need, it permits the fish to feed in a more natural manor.

Below I have listed some of the more common live foods that can be used in an aquarium. My list is by no means complete. It is intended as an introduction only. You can purchase these foods, or even collect them yourself if you wish.

BLOODWORMS & GLASS WORMS – are not worms but the larval form of a fly. Both larvae make an excellent food for mature fish but should not be in a tank with small fry; the larvae are capable of catching and killing the fry.

TUBIFEX WORMS – is probably the most used worm in an aquarium as most dealers stock tubifex worms year around. They can however be found in bodies of water that is rich in organic and vegetable wastes.

MICROWORMS – is a small worm that was discovered to be easily cultivated and made an excellent food for small fish. Other worms that make good fish food include the Grindal worm, White worm and the common earthworm. It is better to not make a steady diet of any one thing. Larger worms should be fed in smaller easier to swallow pieces. To avoid a mushy mess while cutting up the worms use a quick-freeze method. Quickly freeze the worms. When you want to do a feeding, take out the amount of worms needed and cut them with a razor to the desired size.

OTHER – The common housefly is also an excellent food for the fish tank Aquarium. Be aware that only the swatted flies are acceptable as fish food. Flies that have been killed with insecticides are poisonous to the fish that eats them.

Essential advice for starting a home aquarium
Aquarium gravel and water
Aquarium backgrounds explored
Aquarium stands, options and considerations

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Exploring the natural world