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Information about Bristlenose catfish
The humble bristlenose is one of the most commonly kept aquarium fish. They are a keenly sort after addition to aid in algae control and to form part of the clean up crew, consuming uneaten food. There are over 50 species of Ancistrus catfish, some of which are difficult to distinguish from each other. Species identification in Australia is dubious at best and generally speaking the common bristlenose is simply regarded to as Ancistrus sp. They are much smaller than their Plecostomus sp. relatives, however their care is very similar. There are many commonly asked recurring questions posted on the forum, so I thought that an article about these fish was in order.
Common Name: Bristlenose, Bushy-nosed catfish and Sucker-mouth catfish
Scientific Name: Ancistrus sp.
Size (cm) M/F: Both sexes can reach a size of 7 inches, dependent on species.
Habitat: Ancistrus spp. originate from the fast flowing tributaries of the Amazon River. Therefore, their home should reflect the needs of this species. The addition of at least one power head assists in providing well-oxygenated water and currents. Being a mostly nocturnal species, dark gravels/sand is a great choice in substrate. The provision of caves and similar structures will aid in providing security. These home sites may include hollow logs/branches, coconut shells, rock piles or artificial items such as terracotta and ceramic pots. Please ensure that appropriate cleansing methods are followed. By nature, these fish rasp wood, therefore suitable pieces should be included. Wood also provides a great medium for algae to grow on.
Temperature Range: There seems to be a bit of discrepancy in the literature that I have read concerning appropriate water temperature requirements. From personal experience, I have kept and bred bristlenoses in water as cold as 18C. However it would seem that they are not happy when the temperature exceeds 27C. The most probable reasons for this would include the positive correlation between temperature increase and oxygen decrease.
Water Parameters: Fairly soft, slightly acidic to slightly alkaline (pH 6.5-7.5) water is preferred. pH and hardness does not appear to be critical for common Ancistrus spp. as this fish is seems to be hardy and adaptable. Black water extract or the leaching of tannins from wood into the water helps to induce spawning in this species. A negative effect of this discoloration means that algae growth is inhibited due to the impenetrability of light. Stability is by far the most important factor to consider with these species. Sudden changes in water condition will result in unhappy fish. Many medications are toxic to bristlenoses so it is paramount to familiarize yourself with appropriate treatments.
Min. Tank Requirements: A pair of bristlenoses can adequately be housed in a 2-foot tank. Depth is not as important as surface area, so a shallow tank will suffice. Décor and water flow requirements have been discussed above. The type of filtration is not important, however it must be efficient. These fish produce a lot of waste through grazing/rasping activity. Lighting is generally regarded as a negative with these fish, however if illumination time is restricted the fish dont seem to suffer. Many people have said that Ancistrus spp. do not impose upon aquarium plants however I disagree. Delicate plants are especially vulnerable to the rasping action of these fish.
Food: This is by far the most often posed question. By nature, Ancistrus spp. are herbivorous, ie. they require a very high percentage of vegetable matter in their diet. Therefore, their staple diet should consist of a very good quality flake and/or pellet food that is high in vegetable content. Spirulina tablets from the health shop are readily accepted, as are algae wafers. Furthermore, raw or par-cooked vegetables additions should be a regular occurrence (not just as a treat). Examples include cucumber, zucchini, squash, shelled peas, lettuce, Chinese leafy vegetables, spinach, silverbeet, corn etc. Make sure that the vegetables are washed well and weighted down so that they are easily accessible to the fish. Methods of sinking vegetables include par cooking (so that they sink on their own), attaching to a rock with elastic bands and spearing the vegetable with a fork and placing it on the substrate. Lettuce clips can be purchased from LFSs. These devices are suctioned cupped to the side of the tank and the food placed in the peg mechanism. Many people include shrimp, prawn and bloodworms as part of a balanced diet. However, it is important to remember that the vegetable content must be by far the highest dietary component.
Breeding: Males are easily distinguished from females once the fish attain a length of about 5cm. The males grow bristles along the length (up and down) of their nose ridge. Females may grow bristles, but generally they are short and seem to line the upper lip area only. I have never seen forked bristles on a female bristlenose. Females are encouraged to lay a clump of eggs in a sheltered area (such as a cave or inside a log). The clutch is vigorously fanned and protected by the male. It is documented that several females may lay in the same den simultaneously, leaving the male to defend many hundreds of eggs at once. Hatching occurs after about 5 days. The fry then attach themselves to flat surfaces like rock, wood and the sides of the aquarium. The yolk sac is consumed after another 14 days or so at which time you can feed them pulverized green flake food or other baby food. A blanched lettuce leaf, spirulina tablets and algae wafers are also a good choice. Young fish consume a lot of food. It is common to under-estimate the requirements of young bristlenoses and starving is a common reason for high mortality rates. I would avoid moving young fish from the parent tank unless they are larger than 2-3cm. It has also been suggested that the young catfish feed upon the excrement of their parents in order to gain much needed gut flora. They do not like sudden shifts in water parameters. If well fed and cared for, these catfish often spawn and raise families in community tanks. The following three links provide some additional information that may prove useful:
Temperament/Notes: Generally speaking, Ancistrus spp. are amiable amongst tank mates. Males of these species will often fight, especially when trying to attract females for breeding. Sufficient space and spawning sites (caves etc.) will help to subdue the unwanted attention amongst rivals. I have seen opposing males entangled in each others cheek barbs and this sometimes leads to tearing of the said appendages. Coarse, open weave nets should not be utilized to catch bristlenoses, as they will often become tangled. If a fish does become caught up, simply drop the whole net into the tank and leave it for them to disengage from the netting. If this appears to be hopeless, carefully cut the net, leaving the offending piece of gauze attached to the bristles. Eventually it will rot away. These fish are very efficient algae eaters, however they become lazy with age.