That Fish Blog – Aquarium Advice and Information

Hello, 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.

Hello, Frank Indiviglio here. Plankton forms the base of the food chains in all the world’s fresh and marine waters. Comprised of innumerable species of tiny, often microscopic plants and animals, plankton is a very useful but overlooked food source for tiny fish fry, filter-feeding invertebrates and seahorses, pipefishes and other small live food specialists.

Collecting Plankton

Marine waters are undoubtedly the best sources of plankton for seahorses and such creatures, but do not hesitate to try fresh water plankton as well. Just bear in mind that fresh water creatures will perish rapidly in salt water, so don’t overload your tank.

Available through biological supply houses, plankton nets are the most effective means of harvesting this valuable food. Don’t forget to examine your catch with a hand lens or microscope – you won’t believe your eyes!

Using Plankton

When rearing Atlantic seahorse fry at the Staten Island Zoo, I often towed a plankton net behind a boat and by hand from a dock. My efforts were rewarded with an amorphous glob of “organic material”, but the seahorses sure knew what to do with it!  Their reactions were much more vigorous than when presented with their standard meal of brine shrimp, and they grew rapidly.  I have also noticed that northern pipefishes immediately begin feeding when fresh seawater is added to their aquarium…I usually cannot see anything that looks like food, but they do!

I consider plankton to be nearly indispensible for seahorse and pipefish fry, and for adult dwarf seahorses and similar species. But nearly all small fishes and invertebrates, including fresh water species, will eagerly accept plankton as well.  Its use will greatly improve your chances of success with a number of delicate organisms.

Useful Products

Fortunately, “plankton substitutes” are available for those unable to collect their own. “Reef Bugs” are living microbes that are eagerly accepted by corals and other invertebrates. A wide range of other foods for filter feeding invertebrates helps simplify the keeping of these fascinating creatures.

Newly hatched brine shrimp, while not a complete diet for seahorses and pipe fishes, may be nutritionally improved through the use of Artemia food.

Further Reading

The Monterey Bay Aquarium has posted an interesting article on plankton collecting here.

Please write in with your questions and comments.