Post by MADMIKE on May 19, 2007 10:41:22 GMT -5
Unfortunately, it's really a bit of an old wive's tale that adding bottom-feeding fish to your aquarium will make the tank cleaner. Although many bottom feeders will eat scraps of food that have been missed by the other fish, they still need to be fed a diet of their own and will contribute as much dirt to the tank as any other fish.
So you're unlikely to notice an improvement in how clean the tank looks. What they will do is add much-needed interest to the bottom layers since many other aquarium fish are evolved to live in the main water column or just below the surface.
You can usually tell whether a fish is a bottom, surface or mid-water feeder by looking at the position of its mouth. As a bit of a sweeping generalisation, the majority of fish prefer to eat while swimming in a horizontal position: fish that feed from the top have a mouth on top of their head; fish that feed from the bottom have a mouth on the bottom of their head, and fish that feed in mid-water have a mouth in the middle of their face.
There are hundreds of species to choose from, but in general they fall into two categories: loaches and catfishes. Both groups are quite diverse and range in size from small species to large ones, and from herbivores to predators.
Not all loaches, or all catfishes, need the same conditions in the aquarium, so it's important to match the right fish to your tank, your water and your other fish.
Loricariids
Loricariids (pronounced lorry-car-ee-idds) or plecs and are suckermouthed catfishes from South America. Most, but not all of them, are herbivores and feed on algae and microscopic animals living within it, which they will rasp from the surfaces of rocks and bogwood and from the aquarium glass.
Loricariids come in all shapes and sizes, ranging from the tiny Otocinclus which are fully grown at about 5cm/2" to others which can exceed 60cm/24".
Unfortunately, it's some of the biggest species that are most widely sold , so you need to be careful you're not buying something that's going to outgrow your tank. You may run into problems if you don't, and unfortunately, shops are inundated with offers of massive plecs that have been bought by mistake.
In a nutshell, if it's labelled 'Plec' or 'Common plec', don't buy it. Although the shop might tell you it's a Hypostomus plecostomus which only grows to 20-30cm/8-12", chances are it's a Liposarcus multi-radiatus which will get to over 45cm/18". This fish is the leylandii of the fishkeeping world - it grows to a ridiculous size, isn't that attractive to look at, and will be hard to get rid of if it does outgrow your tank.
If you're looking for something more manageable, consider a Peckoltia, Chaetostoma or Ancistrus as the majority of these only reach 10-15cm/4-6" at most.
Loricariids shouldn't be added to new tanks of less than a few months old. Unless you're offering them a plentiful supply of foods, there's unlikely to be sufficient algae for them.
Besides, the water conditions may not have stabilised enough. Plecs are peaceful and will mix well with other fish. They're also armour-plated and can withstand being kept with aggressive fishes without too many problems, making them quite versatile.
If space is limited, take a look at the Otocinclus (and related Parotocinclus) catfishes. These dwarf suckermouths fill much the same niche as larger plecs, but remain at a tiny size with most being fully grown at only 4-6cm/1.5-2.5".
However, because they're rather small, you'll need quite a few of them to keep the tank free of algae. A shoal of 10-12 is really required if your aquarium is over 90cm/36", but on the plus side, they're fairly inexpensive at only a dollar or two each.
Sadly, many of the Otocinclus on sale can be rather sorry looking. Ask your dealer how long the otos have been in the shop before you buy them, and only choose fish that have been in stock for a good few weeks and look fat and healthy.
Sucking loach
The Sucking loach, or Algae loach, Gyrinocheilus aymonieri, is an excellent algae-eater, but it's territorial (especially with members of the same species) and can become aggressive and could rasp the protective mucus from the sides of other fishes.
It's rarely a problem when kept with fast-moving fishes like danios, but can be a nuisance with gouramis and Angels.
Botiines
The loaches in the former Botia genus (pronounced bo-tee-ah) range in size from the very small Chain loach, Yasuhikotakia (formerly Botia) sidthimunki, which reaches about 5.5cm/2" to the fairly big Clown loach, Chromobotia macracantha, which get to as much as 30cm/12" or more, although rarely reaches more than 15cm/6" in the aquarium.
Clown loaches vary in price according to their size and availability. Botia feed predominantly on invertebrates, including small snails and insect larvae, so supplement their diet with bloodworms, brineshrimp or black mosquito larvae.
Some species can be a little nippy, so check with your dealer how the fish will mix with your other fish.
Kuhli loaches
Although they are all given the same label, there are actually several fish sold as Kuhli (pronounced koo-lee) loaches, but their care and require-ments are broadly similar.
The most common are the banded Pangio kuhli and the plain brown P. javanicus. These nocturnal fishes are rarely seen and may only show themselves when food is added. They are very peaceful and unlikely to bother the other fishes, so they make excellent community fish.
They can be added singly, but are happier if kept in groups of three or four, or more. Be careful when choosing Kuhlis as there seem to be some health issues with the fish at the moment, with bacterial infections being especially common. Don't buy any fish if there are any dead ones in the tank, if any of the fish are breathing heavily or have manky-looking patches on their skin.
Corydoras
The Corydoras, or corys as they're also known, make an excellent addition to the community tank. They're small (most reach 5-8cm/2-3"), are peaceful and, in general, fairly easy to keep. There is also a very good range of different species to choose from, many with lovely markings and a cute-looking appearance, and they remain fairly active throughout the day.
Unlike plecs and Sucking loaches, corys do very little to get rid of algae and you will need to offer them specific foods if they are to thrive. In our experience, they don't really do that well if all they get is a diet of scraps from the other fish.
They'll get to a bigger size and be much healthier if you feed them a specialist sinking catfish food, and supplement with frozen bloodworms and the like.
Corys like to be kept in shoals, so don't consider adding them unless you're willing to buy four-six or more. The common species, such as the Bronze catfish, Corydoras aeneus, (which also comes in an albino form) and the Peppered catfish, C. paleatus.
Tank-wise, most of the commonly available corys are fine in a community tank with unadjusted tapwater, even if it's fairly hard and alkaline. Some of the more unusual ones, though, are wild-caught and may need softer, more acidic conditions. Speak to your dealer about their requirements before you purchase them to make sure they'll thrive in your aquarium.
Ideally, corys need a soft sandy substrate - silver or playpit sand is ideal.
This article was first published in the January 2004 issue of the Practical Fishkeeping Magazine.
So you're unlikely to notice an improvement in how clean the tank looks. What they will do is add much-needed interest to the bottom layers since many other aquarium fish are evolved to live in the main water column or just below the surface.
You can usually tell whether a fish is a bottom, surface or mid-water feeder by looking at the position of its mouth. As a bit of a sweeping generalisation, the majority of fish prefer to eat while swimming in a horizontal position: fish that feed from the top have a mouth on top of their head; fish that feed from the bottom have a mouth on the bottom of their head, and fish that feed in mid-water have a mouth in the middle of their face.
There are hundreds of species to choose from, but in general they fall into two categories: loaches and catfishes. Both groups are quite diverse and range in size from small species to large ones, and from herbivores to predators.
Not all loaches, or all catfishes, need the same conditions in the aquarium, so it's important to match the right fish to your tank, your water and your other fish.
Loricariids
Loricariids (pronounced lorry-car-ee-idds) or plecs and are suckermouthed catfishes from South America. Most, but not all of them, are herbivores and feed on algae and microscopic animals living within it, which they will rasp from the surfaces of rocks and bogwood and from the aquarium glass.
Loricariids come in all shapes and sizes, ranging from the tiny Otocinclus which are fully grown at about 5cm/2" to others which can exceed 60cm/24".
Unfortunately, it's some of the biggest species that are most widely sold , so you need to be careful you're not buying something that's going to outgrow your tank. You may run into problems if you don't, and unfortunately, shops are inundated with offers of massive plecs that have been bought by mistake.
In a nutshell, if it's labelled 'Plec' or 'Common plec', don't buy it. Although the shop might tell you it's a Hypostomus plecostomus which only grows to 20-30cm/8-12", chances are it's a Liposarcus multi-radiatus which will get to over 45cm/18". This fish is the leylandii of the fishkeeping world - it grows to a ridiculous size, isn't that attractive to look at, and will be hard to get rid of if it does outgrow your tank.
If you're looking for something more manageable, consider a Peckoltia, Chaetostoma or Ancistrus as the majority of these only reach 10-15cm/4-6" at most.
Loricariids shouldn't be added to new tanks of less than a few months old. Unless you're offering them a plentiful supply of foods, there's unlikely to be sufficient algae for them.
Besides, the water conditions may not have stabilised enough. Plecs are peaceful and will mix well with other fish. They're also armour-plated and can withstand being kept with aggressive fishes without too many problems, making them quite versatile.
If space is limited, take a look at the Otocinclus (and related Parotocinclus) catfishes. These dwarf suckermouths fill much the same niche as larger plecs, but remain at a tiny size with most being fully grown at only 4-6cm/1.5-2.5".
However, because they're rather small, you'll need quite a few of them to keep the tank free of algae. A shoal of 10-12 is really required if your aquarium is over 90cm/36", but on the plus side, they're fairly inexpensive at only a dollar or two each.
Sadly, many of the Otocinclus on sale can be rather sorry looking. Ask your dealer how long the otos have been in the shop before you buy them, and only choose fish that have been in stock for a good few weeks and look fat and healthy.
Sucking loach
The Sucking loach, or Algae loach, Gyrinocheilus aymonieri, is an excellent algae-eater, but it's territorial (especially with members of the same species) and can become aggressive and could rasp the protective mucus from the sides of other fishes.
It's rarely a problem when kept with fast-moving fishes like danios, but can be a nuisance with gouramis and Angels.
Botiines
The loaches in the former Botia genus (pronounced bo-tee-ah) range in size from the very small Chain loach, Yasuhikotakia (formerly Botia) sidthimunki, which reaches about 5.5cm/2" to the fairly big Clown loach, Chromobotia macracantha, which get to as much as 30cm/12" or more, although rarely reaches more than 15cm/6" in the aquarium.
Clown loaches vary in price according to their size and availability. Botia feed predominantly on invertebrates, including small snails and insect larvae, so supplement their diet with bloodworms, brineshrimp or black mosquito larvae.
Some species can be a little nippy, so check with your dealer how the fish will mix with your other fish.
Kuhli loaches
Although they are all given the same label, there are actually several fish sold as Kuhli (pronounced koo-lee) loaches, but their care and require-ments are broadly similar.
The most common are the banded Pangio kuhli and the plain brown P. javanicus. These nocturnal fishes are rarely seen and may only show themselves when food is added. They are very peaceful and unlikely to bother the other fishes, so they make excellent community fish.
They can be added singly, but are happier if kept in groups of three or four, or more. Be careful when choosing Kuhlis as there seem to be some health issues with the fish at the moment, with bacterial infections being especially common. Don't buy any fish if there are any dead ones in the tank, if any of the fish are breathing heavily or have manky-looking patches on their skin.
Corydoras
The Corydoras, or corys as they're also known, make an excellent addition to the community tank. They're small (most reach 5-8cm/2-3"), are peaceful and, in general, fairly easy to keep. There is also a very good range of different species to choose from, many with lovely markings and a cute-looking appearance, and they remain fairly active throughout the day.
Unlike plecs and Sucking loaches, corys do very little to get rid of algae and you will need to offer them specific foods if they are to thrive. In our experience, they don't really do that well if all they get is a diet of scraps from the other fish.
They'll get to a bigger size and be much healthier if you feed them a specialist sinking catfish food, and supplement with frozen bloodworms and the like.
Corys like to be kept in shoals, so don't consider adding them unless you're willing to buy four-six or more. The common species, such as the Bronze catfish, Corydoras aeneus, (which also comes in an albino form) and the Peppered catfish, C. paleatus.
Tank-wise, most of the commonly available corys are fine in a community tank with unadjusted tapwater, even if it's fairly hard and alkaline. Some of the more unusual ones, though, are wild-caught and may need softer, more acidic conditions. Speak to your dealer about their requirements before you purchase them to make sure they'll thrive in your aquarium.
Ideally, corys need a soft sandy substrate - silver or playpit sand is ideal.
This article was first published in the January 2004 issue of the Practical Fishkeeping Magazine.
