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Live Foods for Marine and Freshwater Fishes – Worms and Worm Look-a-likes

PolycheteHello, Frank Indiviglio here.  Marine, grindal, micro, white, blood and other worms drive even the most peaceful aquarium fishes wild, and with good reason – they figure prominently in diets worldwide, and are packed with important nutrients.  Research in which I was involved (Bronx Zoo) has shown that earthworms form a near-perfect diet for many amphibians, and may likely be so for certain fishes as well. 

Blackworms are a pet trade staple…today I’d like to mention a few lesser-known types.

Marine Worms, Families Neridae and Annelidae

Sandworms, bloodworms and other large marine species are seasonally available at bait stores or, where legal, may be collected under rocks along bays and tidal streams.  They are an expensive but important component of the diets of a great many saltwater fishes and invertebrates.

Several species have sharp mouthparts and can deliver a painful bite, and may be dangerous to aquarium pets as well….in fact, the hard jaw material of one sandworm is being put to industrial uses.  It is usually prudent to remove the head before feeding. 

Marine worms store well packed in seaweed under refrigeration.  They are interesting aquarium animals in their own right – please look for a future article on their care.

Microworms, Anguillula silasiae and Grindalworms, Enchytraeus bucholizi

Grindalworms are related to earthworms; microworms are not true worms, but rather nematodes. 

Both breed well in damp peat moss at 75 F, and feed upon vegetable-based tropical fish flakes.

Whiteworms, Enchytraeus albidus

Closely related to grindalworms, whiteworms fare better at cooler temperatures (50-58 F) and may be fed oatmeal and staple diet fish flakes.  Cultures are commercially available.

Bloodworms, Chironomus spp.

Unlike marine bloodworms, Chironomus are the aquatic larvae of tiny flying insects known as midges (“gnats”).  Interestingly, they utilize a form of hemoglobin to transport oxygen in the blood, much as we do.

Bloodworms are impractical to breed but are available at pet stores, and survive well under refrigeration.  Like other freshwater invertebrates, bloodworms may be fed to marine creatures, but they spoil rapidly in salt water.

Further Reading

Earthworms are the most useful of all invertebrates…a breeding colony will supply the needs of fishes and invertebrates of all sizes.  Please see my article Rearing and Using Earthworms for further information.

For an interesting article on sandworm behavior and breeding habits, please see this article.

Please write in with your questions and comments. 

Thanks, until next time,

 Frank Indiviglio.

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About Frank Indiviglio

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Being born with a deep interest in animals might seem unfortunate for a native Bronxite , but my family encouraged my interest and the menagerie that sprung from it. Jobs with pet stores and importers had me caring for a fantastic assortment of reptiles and amphibians. After a detour as a lawyer, I was hired as a Bronx Zoo animal keeper and was soon caring for gharials, goliath frogs, king cobras and everything in-between. Research has taken me in pursuit of anacondas, Orinoco crocodiles and other animals in locales ranging from Venezuela’s llanos to Tortuguero’s beaches. Now, after 20+ years with the Bronx Zoo, I am a consultant for several zoos and museums. I have spent time in Japan, and often exchange ideas with zoologists there. I have written books on salamanders, geckos and other “herps”, discussed reptile-keeping on television and presented papers at conferences. A Master’s Degree in biology has led to teaching opportunities. My work puts me in contact with thousands of hobbyists keeping an array of pets. Without fail, I have learned much from them and hope, dear readers, that you will be generous in sharing your thoughts on this blog and web site. For a complete biography of my experience click here.