Chapter 1 – Understanding Aquarium “Eels”

The long, snake-like fish kept by enthusiasts in both fresh and saltwater aquariums that are commonly referred to as “eels” may be true eels from the order of Anuilliformes, or any one of a number of “eel-like” fishes.

American Eel - Morrison Springs

Anuilliformes are elongated fish. They include members of the family Anguillidae like the American Eel and the European Eel, or those found in the family Moringuidae like Worm Eels and Spaghetti Eels.

Spiny Eels, however, are actually “eel-like” fish. They belong to the Mastacembelidae family. Even the well-known Electric Eel (Electrophorus electricus) is actually a Naked-Backed Knifefish (family Gymnotidae.) And Rubber Eels aren’t eels or fish, but amphibiains!

Basically, just because it looks like an eel, doesn’t mean it actually is an eel.

Characteristics of True Eels

All true eels have a laundry list of readily identifiable characteristics including:

  • elongated bodies
  • a snake-like appearance
  • no pelvic fins
  • no pectoral fins
  • no gill cover openings
  • no scales
  • continuous dorsal and anal fins
  • locomotion via flowing, undulating strokes
  • mucous covering for protection against abrasions

Moray eels, in particular, have lateral line pores on their heads. This allows them to hide in crevices and caves with just their heads sticking out while still being able to sense movement in the surrounding water.

In many cases the creatures characterized as “eel-like” fish have none of these special adaptions, but they do have elongated bodies. Because making these distinctions can be very difficult for all but the experts, I am choosing to go with more simplified language.

Using the Term “Eel”

For the purposes of this text, I will discuss “aquarium eels” as a group of eels, fishes, and even amphibians that share the common characteristic of having long, snake-like bodies. These creatures may live in salt or fresh water. Most consume similar diets, and are intelligent fish with a penchant for staging escapes.

If there is one rule of thumb with which to begin your interest in keeping eels it is this: cover your tank, tightly!

The following chapters will provide descriptions of the most popular eels kept by aquarists and look at specialized aspect of their husbandry including the design of tunnels and hiding spaces.

While this book is not intended as a “how to” aquarium book per se, I think it’s important to provide an overview of some of this material, especially for those readers still sitting on the fence about whether or not to take up this pastime.

Be forewarned. Designing and keeping an underwater environment, especially one you have created around a showcase species like a prized eel, can be an all-consuming passion – and an expensive one.

Many of these eels require huge tanks, so large in fact that you may even find yourself reinforcing the floors in your house to accommodate the weight of the water.

For this reason, many eel enthusiasts are forced to dial back their expectations and settle for incorporating smaller “eel like” fish in their tanks. This does not have to be seen as a compromise, however, as many of these creatures are both beautiful and intriguing.

To begin with, however, we will look at some of the largest and most popular eels kept by saltwater aquarists, the moray eels. They are all aggressive carnivores and cannot simply be introduced into any existing saltwater tank without serious considerations of population management.

Buying Aquarium Eels

By and large, the various “eel-like” fish are not difficult to find and can be obtained from any good aquarium store. For larger and rare eels, you may find yourself shopping online.

As an example, Live Aquaria at offered about half a dozen species at the time of this writing in mid-2014. Of those, four were marked “seasonal” or “out of stock.”

The site offers a “100% arrive alive, stay alive” 14-day guarantee with the option for a refund or account credit. They are located in Rhinelander, Wisconsin. The company cannot ship to Hawaii, APO addresses, post office boxes, Puerto Rico, U.S. territories, or internationally.

Always read the shipping policies of any entity with which

you deal. In most cases, you or someone else will need to be waiting to accept the shipment and care for the eel. Making the best arrangements will likely necessitate a telephone call.

In the UK, look at Tropical Fish by Post at They deliver in England, Wales, Scotland, and Ireland. At the time of this writing, the site listed three species, but only the Tire Track Eel was in stock.

Continue Reading…

Pin It on Pinterest