Animal-World > Freshwater Fish > Freshwater Eels and Eel-like Fishes > Black Spotted Eel

Black Spotted EelPolka Dot Eel ~ Spotted Spiny Eel

Family: Mastacembelidae

• Puzzles
• Postcards

Mastacembelus dayiPhoto © Animal-World: Courtesy Ken Childs

    The Black Spotted Eel may not be brightly colored but it has a beautiful design!

     The Black Spotted Eel is also known as the Polka Dot Eel or Spotted Spiny Eel. As you can see in the photo above it sports an exotic looking color pattern. Smaller specimens have fewer but larger spots. This elegant patterning makes it a beautiful fish, one that is well worth having in your aquarium.

     The Black Spotted Eel has been imported for a long time, and over the past few years many thousands have been shipped from Thailand. Mastacembelus dayi is considered to be very rare by science, but fortunately this is probably not true. Supposedly only 3 specimens have ever been found and these 3 were used to describe the species. This is probably just a case of local fisherman knowing more about the distribution of a fish than the scientists do.

     As with most members of the spiny eel family, the attractiveness of this eel lies in its unusual color pattern and interesting behavior. Although not considered to be true eels, the body shapes of all members of the spiny eel family, Mastacembelidae, are definitely eel-like.

For more Information on keeping freshwater fish see:
Guide to a Happy, Healthy Freshwater Aquarium

Distribution:      The Black Spotted Eel, called Polka Dot Eel or Spotted Spiny Eel, was described by Boulenger in 1912. They are found in Asia; western Myanmar and eastern Thailand.

Status:      The species is not listed on the IUCN Red List.

Description:      The Black Spotted Eel is elongated with a long snout. Its background coloration is a dark tan to light brown. Along the length of its body it has a series of spots in a linear fashion. The spots are relatively large, with those on the upper part being dark and those lower down becoming paler. Some of the spots, especially along the center, can often become vertically elongated rather than round. This patterning extends from the tip of its mouth to the rear of the fish. Smaller specimens have fewer but larger spots.

Size - Weight:      Fish of over 20 inches (50cm) are commonly imported. Science lists the maximum size at about 12 inches (30 cm) but since they were working with only 3 fish, this information is probably wrong.

Care and feeding:      The Black Spotted Eels are carnivores. Feeding is not a problem because they will eat most fresh or frozen foods including small fish, worms, and shrimp. They may be trained to eat freeze dried brine shrimp or bloodworms but this is not something that can be counted on. They will also eat small fishes so make sure their tank mates are too large to be able to fit into their mouths.
     They should have a tank with fine gravel or sand because they like to bury themselves. Make sure they have plenty of hiding places so they will feel secure in their new home. It is advisable to keep small specimens, those up to 6 inches, in a tank that is at least 36 inches long and about 35 gallons. Larger specimens will needing an even bigger area, tanks that are 48 inches in length or longer and 55 gallons and up will be necessary. Provide a tight fitting lid as spiny eels are escape artists. These fish respond poorly to copper based medications, so these should be avoided.

Water Region: Top, Middle, Bottom:      Black Spotted Eels with stay on the bottom of the aquarium.

Acceptable Water Conditions:      Temp: 74 - 82 ° F (23 – 28 ° C)
     Hardness: 6 - 25 dGH
     Ph: 6 - 8

Social Behaviors:      Like most spiny eels, they are not aggressive but due to their large size mouths, they may eat smaller tank mates.

Sexual Differences:      Sexual differences are unknown.

Breeding/Reproduction:      Has not been bred in captivity.

Availability:      Black Spotted Eels, also called the Polka Dot Eel or Spotted Spiny Eel, are commonly available.

Add your comment here!
Latest Comments
Hello animail world. I'm new here and I just bought a black spiney eel and he's great, he's about 5 inches long. He's amazing. Anyways take that one part very serious about them being ecape artists, cuz it's true. No more then 6 hours of having him he tried escape number 1, and I also noticed that they are really night time fish and they need fast moving fish. He started to attack my tiger barbs. I don't know what he's gonna do with my other tiretrack eel, hopfully it'll be a happy tank. Todd 2010-01-31
I bought a spotted eel at a place in portland called the wetspot you can google them it comes up easy. good luck Anonymous 2010-01-04
Where can I buy this fish, I'm tired of looking for him. I live in portland or if anyone can give me the number to where they really have it, would be nice. thanks! cesar 2009-07-03
Hello, I'm new to this site. So far I have found it fascinating and extremely educational. I own two Clown Knife fish that I purchased about 5 months ago from a local pet store. (The told me the specimens were "African Clown Knife fish") -shrug- Anyway, I was wondering if the Black spotted Eel would get along with my Knife fish? The larger of the Knife fish is roughly 7-8" and the smaller about 6-7 1/2" I was thinking (if they would get along) about purchasing a Black Spotted Eel, probably 5-6 1/2" Some advice would be much appreciated. Thank you, Marine Life Momma Anonymous 2008-12-11
Hi I have what i believe is a spotted eel, and i love it. I ne ver knew such thing exists until a friend told me. However, i want to know how to stock live shrimps and to breed them ... any advise on what is required to breed river/ghost shrimps? carol 2008-08-26

Back to Freshwater Eels and Eel-like Fishes