Fish, Tanks and Ponds


Fish, Tanks and Ponds
A comprehensive guide to fish

Polypterus

Barred bichir, Polypterus delhezi
Barred bichir, Polypterus delhezi

Bichirs and ropefish

Introduction

The name Polypterus is derived from the word Polypteron which itself is made from two Greek words Poly(= a lot of) and Pteron(= wing) so Polypterus means many wings and probably refers to the many separate dorsal fins of the fish in this family. The family contains two genera and possibly up to 18 species and subspecies.

  • Polypterus ansorgii, 28cm (11")
  • Polypterus bichir, 74cm (27")
  • Polypterus congicus, 97cm (39")
  • Polypterus delhezi, 44cm (17")
  • Polypterus endlicheri, 63cm (25")
  • Polypterus mokelembembe, 23cm (9")
  • Polypterus ornatipinnis, 60cm (24")
  • Polypterus palmas, 35cm (14")
  • Polypterus polli, 32cm (13")
  • Polypterus retropinnis, 34cm (13")
  • Polypterus senegallus, 70cm (28")
  • Polypterus teugelsi, 41cm (16")
  • Polypterus weeksii, 41cm (16")
  • Erpetoichthys calabaricus, 41cm (16")

Polypterus

The Polypterus Genus is found in East and West tropical Africa in lakes and slow moving rivers.

They are very tolerant of a wide range of conditions because they are able to breathe atmospheric oxygen. This enables them to leave the water if it becomes to polluted and use their strong pectoral fins to move across land to a new and more suitable body of water.

Polypterus have become so reliant on their ability to breathe directly from the air that even in oxygen rich water they still need to come to the surface for a gulp of air and they will drown if they are prevented from doing so. There are two lungs and they are unequal in size, the right lung runs the entire length of the body but the left lung is shorter to accommodate the stomach and intestine. It is difficult to tell the sexes apart but when adult the males are generally larger and have a broader anal fin.

They are an ancient fish and fossil records show that lineage goes back over 65 million years and in all that time they have changes little. 65 million years ago most of the true bony fish had lungs and ganoid scales just like today's Bichirs. There are some other fish still around today with ganoid scales and some with a similar shape to the Polypterus but the structure at the base of the paired fins is completely different and this means that they aren't closely related.

The fry of some species have external gills when they first hatch and these are slowly absorbed into the gill covers as the fish matures. Some species have bred in captivity but this is quite rare.

They are all predators and hunt other fish during the hours of darkness. They will take other prey too, worms, frogs, fish it doesn't matter whether the prey is alive or dead, if it will fit in their mouth they will eat it. Fish that are to big to eat will not be molested but they may quarrel among themselves if there aren't enough hiding places.

Captive Care.

Housing

Some Bichirs grow big and need a suitably large aquarium. But these are not fish which require large open areas to swim in because they tend to be fairly inactive preferring to hide in plant thickets so the tank doesn't have to be as big as it does for a similar sized Silver Shark or Tinfoil Barb.

As long as the fish can stretch out along the width of the tank and manoeuvre with out any problem then just use common sense and check the adult size of the species that you are interested in.

The aquarium needs to be well covered because these fish are great escape artist and will find the tiniest of gaps. If you find an escapee even if it feels quite dry it is worth returning it to the water because they can survive for a very long time out of water and it may come to and survive.

The best thing is to avoid it happening by using a strong and heavy condensation tray and make sure their are no gaps. Tank size needs to be adequate for the species being kept, and it must include sufficient hiding places for all the occupants if it is to remain peaceful.

Conditions

They will accept a wide range of conditions but the different species do have different preferences which should be met if possible. But they will all be quite happy as long as extremes in pH and hardness are avoided.
A temp in the range of 76F to 82F will suit them.
A busy tank with bogwood roots and plants will keep them content because they need to feel secure and a wide open space could make them shy. Bright lighting will also encourage them to hide.

Food and Feeding

Polypterus and their close relative are carnivores although some will occasionally accept Cichlid pellets. A good variety of food will help keep them healthy and will avoid dietary related problems associated will a diet which is to narrow.

  • Whitebait.
  • Lance fish.
  • Prawns.
  • Earthworms.
  • Crickets.
  • Bloodworms.

Will all make a good diet for them. Fresh or frozen food is preferable to live food because they aren't the most efficient or fast hunters and any live fish used as food would spend quite a long terrifying time being chased before it was caught and that is unacceptable and pointless because dead prey is just as acceptable to them. Don't use sick fish as food for obvious reasons. With a fish based diet there is a risk of vitamin deficiency because of a chemical within the body of all fish which breaks down vitamin B. To counter this you should soak the food fish in a product like Kent Zoe which is a vitamin additive for fish, and by using enough of the non-fish items as food too.

Lighting

This should be kept subdued, or if you have live plants make them very dense so that the floor is kept relatively dim, Polypterus are normally nocturnal and they will be very shy in bright lighting.

Observations of my Bichirs

I have kept a total o; five individual Bichirs in all from three species.

P. senegallus,

These are by far the most active of the three and the least shy. They actively swim about most of the time they are curious and keen to investigate anything new. They don't fight either amongst themselves or with other fish. This species is quite plain but they stay at a manageable size they are easy to feed and care for. This is probably the best species to get for your first Bichir or if you want to make a nice display.

P. ornatipinnis,

This species is one of the nicest looking fish in the family. Mine are very shy and they rarely venture out during the day except for feeding. They are also a little more quarrelsome among themselves and they try to take the food off other fish. These also grow larger than the previous species and will need a bigger tank. They are efficient predators and are capable of capturing much faster and more agile species.

P.  congicus,

This is a large and powerful species, I had to make an heavier condensation tray because mine kept lifting the old one off with ease. I have mine in with a variety of other fish without any problems. He is content to slowly move around the tanks floor looking for morsels of food he does stay out in the open during the day time but he isn't very active. He also took a little longer to settle in and initially he refused to eat for almost a week. Now that he has settled he is feeding well and so far he has been entirely peaceful despite being the largest fish in the tank.

Erpetoichthys calabaricus

Commonly called the Rope fish or Reed fish and is a very close relative of the Bichirs but it lacks pelvic fins which are present in Polypterus. They are found in Nigeria and Cameroon in Africa. They can reach a length of 16" in the wild but usually less in the aquarium. These fish are the greatest of all escape artist and any small gaps must be plugged, even where air pipes and wires enter the aquarium.
They prefer acidic water pH 6.5 to 6.9, hardness isn't critical but avoid extremes. And Like the Bichirs it is mainly a nocturnal hunter using smell to locate it prey. They are peaceful fish and several can be kept together without a problem. But other tank mates must also be peaceful and to big to be considered as food. Their tank should be full of bogwood and plants to make them feel secure and allow them to hide if they wish. Ironically giving them more hiding places will eventually lead to them coming out more.

Important.

All Polypterus are very well known for jumping out. It isn't a case of "if" but more a case of "when". Make sure they are very well covered at all times and plug any small gaps where the wires or air pipes enter the tank or sooner or later one will escape. When they have grown to adult size these are powerful fish so the cover as well as being complete also needs to be heavy so that it cannot easily be dislodged.
If the worst happens and one does escape and you discover it some time later don't automatically assume the worst. These fish have a primitive lung which allows them to stay alive out of water for quite some time. So the first thing to do is to return it carefully to the tank and see if it is alive.
If it is it will need some tlc for a while until it can be nursed back to full health.
To begin with it will have lots of abrasions and bruising. So to prevent secondary infection use a broad spectrum anti bacteria/fungal remedy such as Interpet No 9 Anti Internal Bacteria, despite the name it is a great product for this sort of thing because it stays active in the water for quite sometime and give the fish time to start healing. A dose of stress coat will also help in this situation and so long as the fish can then be left in peace (ideally in its own tank) no further treatment should be necessary.

Bichir and Reedfish

Erpetoichthys calabaricus
Reedfish

Polypterus delhezi
Barred Bichir

Polypterus ornatipinnis
Ornate Bichir

Polypterus senegalus
Senegal Bichir


Congo Bichir