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Keeping the Frogfish

by Kenneth Wingerter

The marine aquarium hobby has been dominated by corals–reef tanks–for quite a while now. As a consequence, over time, aquarists have shied away from many of the cool predatory fish groups in favor of “reef-safe” types. For sure, the designation of reef-safe doesn’t necessarily suggest a peaceful disposition; just think back on some of the tangs or dottybacks you’ve owned. Conversely, some predators are actually quite peaceful in the sense that they don’t attack any animals that they cannot swallow. Indeed, many of these predators won’t even harm corals. The only thing that disqualifies their reef-safeness is their tendency to consume smaller fish as well as shrimps, clams, etc. 

That all being said, the somewhat vague and fluid term “reef-safe” certainly might be stretched to include a less conventional, large reef aquarium community featuring groupers, lionfish, tuskfish, puffers, moray eels, etc. In other words, a community that may include predators so long as they are not coral predators. While these fish cannot be trusted with small, vulnerable, tasty animals of certain kinds, they will (more or less) spare your corals. But they get do get BIG and require oversized aquaria. There are exceptions to this, however; one such exception is the frogfish. 

Frogfish are a group of small (usually less than four or five inches length), shallow-water anglerfish that make up the family Antennariidae. Most if not all of the anglers you’ll ever encounter in the aquarium trade belong to this family. One big reason for this (in addition to the fact that many anglers live in very deep water) is that most of the other anglerfishes grow to large sizes. In addition to their modest mass, frogfish are (like most of their angler brethren) extremely slow-moving, low-energy animals and therefore can be kept in relatively (we stress relatively) small tanks.

Frogfish natural history

Antennariids occur in nearly all tropical and subtropical marine waters (with one notable exception being the Mediterranean Sea, oddly enough). The greatest abundance of frogfish lies within the tropics, with Indonesia being a particularly rich frogfish hot spot.

Unlike so many of their anglerfish cousins which typically inhabit the dark abyss, frogfish tend to stick to the shallows (<100 meters depth). Frogfish habitat in general consists of rubbly, but fairly open, bottoms. The stone or coral rubble often is covered with seaweed, sponge, and/or other sessile organisms. Frogfish are masters of camouflage and mimicry, bearing adaptations such as body textures and colors that match their surroundings. In many instances, the animal blends in so well with its surroundings (including associated seaweed, sponge, etc.) that it may be difficult to see even when you’re looking right at it and know that it’s there.

The short, stocky body of the frogfish is without scales. The skin may, however, be covered with tiny projections called spinules. A specialized dorsal fin spine, called the illicium, works like a fishing rod to entice and drawn in prey (in a just few species, the illicium is absent). The illicium is topped with what is called an esca, which acts as the lure. Every frogfish species has a unique esca; some resemble tiny shrimp, whereas some resemble worms, and some just look like little blobs. What is strange is that even though each species’ lure is quite distinct, all species have generalized diets that include virtually animal they can swallow (shrimp, small cephalopods and other fish including members of their own species).

Frogs in the reef

Forget that these animals are not particularly colorful, flashy or active. They absolutely do make amazing and unusually rewarding fish to keep. And, as indicated earlier, they do not require a particularly large amount of living space. They are not especially picky about water quality and rarely succumb to disease. Overall they are quite easy to maintain, but for one thing: Feeding.

This isn’t a fish that will swim around nibbling pellets off of the aquarium sand. Frogfish are exclusively predatory and only accept whole, real foods. Some only accept live foods. This presents a few potential husbandry challenges. First, maintaining a steady supply of relatively large live food items (goldfish, ghost shrimp, etc.) can be costly and time-consuming. Then (in order to ensure highest nutritional quality of the live food), one must go through the extra effort of gut-loading the prey with a wholesome item (e.g. fortified spirulina flakes) just prior to feeding the frogfish. Then, you have to hope that the prey ends up in the frogfish’s mouth before it succumbs to the salty water. 

This is where smaller tanks actually assist in keeping a frogfish. In a small tank, the prey is always closer to the predator. Sure, you cannot keep active predators in a small tank, but those fish wouldn’t work anyway since they’d always steal the frogfish’s food. Certain small, slow ambush predators such as dwarf lionfish and waspfish, however, are appropriate tankmates since they have similar feeding requirements. In fact, it is possible to feed each individual in this manner with tongs. Once trained to accept food off of the tongs, you may even be able train them (including the frogfish) to accept frozen fare such as silversides.

And the aquascape itself? There’s not much to it; just some rubble rock on the bottom and you’re good to go! These fish aren’t very picky about that, so long as they have some rock to walk over and grab onto with their hand-like pectoral fins.

A moderately sized species tank is best for both these non-social creatures and their keeper. This makes keeping them even more easy and enjoyable. For sure, such a tank is a great diversion from the typical rigors of the “normal” reef tank!

Reader Interactions

Comments

  1. Virginia Dominguez says

    Good reading!
    Frog fish are very interesting fish though I don’t think they are for me due to their feeding habits. I just could not put a poor fish to death to feed it.?

    Reply

  2. ryorzins says

    This would make an unusual, colorful, interesting addition to the right tank. Love the red colored guy in the photo.

    Reply

  6. Brian Veach says

    I’ve often thought about the term reef-safe and if it was fair to apply to any fish. Really though, it isn’t fair to call 1 fish not reef-safe based on a few particular traits. Good article and I’ll look into frogfish!

    Reply

  16. Mark Weber says

    I wish they were reef safe and community fish. If I’m setting up another tank I’m gonna want to add corals and more fish! ?

    Reply

  17. Mark Weber says

    I wish they were reef safe and community fish. If I’m setting up another tank I’m gonna want to add corals and more fish! ?

    Reply

    • Eric says

      I’ve always been fascinated by these specimens. If I had the room right now I would definitely do a species only tank of one! Very good reading as well!

      Reply

    • Eric says

      I’ve always been fascinated by these specimens. If I had the room right now I would definitely do a species only tank of one! Very good reading as well!

      Reply

  54. James Bradshaw says

    Always wanted to setup a predator tank since it’s so much less extensive than a reef tank. Frog fish would definitely be one of the habitants if I ever do it

    Reply

  68. jason_lifted35 says

    Frogfish are definitely are one of the coolest/strangest fish that we keep in reef tanks. Crazy colors and character.

    Reply

  76. Raven says

    pretty cool fish do you guys help protect the issues of how coral has been dieing more recently too.I didn’t know frogfish where in the angel fish family both beautiful

    Reply

  105. ekersd says

    We need captive breeding to make these guys more predictable to feed and stop wild collection of these super cool creatures.

    Reply

  110. blackadonai says

    Great read. I’d like to have a frogfish but I would have to set up a whole new system since I don’t think they’d do well in my reef tank and they certainly can’t go in the seahorse tank I have cycling

    Reply

  113. Brandon says

    These are some of the most fascinating fish to me – I’d love to keep one in a dedicated environment someday… maybe after I upgrade my nano.

    Reply

  122. markwdunlap88 says

    Noway I could keep something like that on my bedroom dresser without having nightmares haha! No offense frogfish!

    Reply

  126. crplcarott says

    Interesting fish. But even with me owning a smaller aquarium I don’t think it would be a good fit.

    Reply

  136. Donald says

    Great I formation. Wish I had this kind of details before I had gotten mine. Had it for months until it decided to swallow a clown as big as itself. Both died from it. All in all it was an amazing fish

    Reply

  148. Joseph Emm says

    These are rather cute but being that they are predatory i just cant bring myself to feed a live fish to another fish for my enjoyment. all of my aquaria are lacking in the “predator” department. However for those that have the stomach for it, these seem to be a good addition to a larger tank that needs some …dare i say… feet on the ground ;D

    Reply

    • Raven Scholtz says

      Frogfish are not a reef-safe species. These fish do well in tanks with live rock and happily co-exist with corals. Smaller fish and inverts are likely not safe with them as they are exclusively predatory.

      Reply

  168. Britney New-Day says

    The yellow and purple variety has always been a dream fish. The live feeding has always been the thing blocking me from getting one.

    Reply

  178. Jonathan says

    We had a frog fish for many years. Our biggest tip is do not feed them any bloated live fish. Any air in the frog fish would make you have to burp it. Which was a pain and stressful for the fish. They are awesome just really think about the responsibility of that fish they don’t move much and the cameo makes the tank look empty.

    Reply

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