Otos are one of our favourite fish in the planted aquarium. We used to think that bristle nose catfish were perfect for algae eating but we’ve found as they get older they don’t eat much algae at all and are constantly digging up the plants and gravel. Not that otos are only good for algae eating, but they can rid your aquarium of brown algae almost over night! They are sucker mouth catfish and are most often viewed from their underside as they hang on your aquarium glass. This gives a perfect view of their pearly white bellies, showing whether it is time to feed them again or not depending on how plump their bellies are. Before first keeping otos we had only seen pictures on the internet of their underside against the glass and so didn’t know they were spotted brown and slightly hairy on their backs! They are often mistaken for Otocinclus afinis however the macrospilus is a mottled brown colour with a distinct white lateral line running from its nose to its tail. The macrospilus is much more common in the aquarium trade but both species have the common name ‘dwarf oto’ and the afinis has a more golden sheen to it. Otos are best fed spirulina discs and should not be introduced to the aquarium until it is slightly mature with some algae present. They can be a bit shy and prefer to eat just after the lights go out.
All otos being sold at the moment are wild caught with only a handfull of people claiming success in captive breeding. Being wild caught means that most otos, once established, are very robust with good genes. Being a popular and seasonal fish can mean that otos are sometimes hard to source with most being imported via Germany. Otos are very sociable fish and like being kept in groups of at least two. They graze by jumping from leaf to leaf in groups and for this reason are sometimes refered to as little monkeys.
Corys are bottom dwellers from the shoals of the tributaries and rivers of South America and make an excellent addition to any planted aquarium. This particular species is quite small, only getting to about 5cm in length unlike the 10cm that some of the larger corys can grow to. The distinctive dark diagonal line over their eyes and their spotted body identifies them as being fairy corys. If the dark line is faint enough and their spots fine enough they can be confused with C. julii, a more rare and expensive cory. In their natural habitat corys forage for insects and vegetable matter in the substrate using their barbels.In our aquarium we feed them a complete sinking pellet for bottom dwellers and invertebrates (nutrafin sinking complete tablets). Cory barbels are sensitive and can be cut or torn easily on any sharp or rough edges of the substrate. For this reason it is recommended that you use a substrate that is rounded such as round gravel (sand), dupla ground, eco complete or aquasoil. Seachem’s flourite, while great for growing plants in, is not very suited to keeping corys.
We have actually seen the signature cory defence called “Cory Torpedo” in the aquasoil one day. Our fattest cory, Lucille, was trying to escape our fish net while being moved to another tank. The defensive move involves them gathering speed and diving head first into the substrate until their body is about half buried. One thing to remember with the softer semi-fired clays like aquasoil is that the corys foraging will stir up a lot of dust and cloud the water. While this is not necessarily harmful to the corys it is aesthetically a little unsightly. Corys like to be kept in groups of at least 3 to 6 and can be a bit timid so give them plants, rocks or driftwood in the tank to hide and swim behind. You need to be a little carefull ith your choice of plants as their constant foraging will dig up small rooted species such as HC and nardoo.
