Our purpose in designing this page is to enable you to identify an organism and make an informed choice of how to deal with it. There are many types of small worms and other critters that inhabit aquatic habitats. Some arrive in your tank or pond by accident and some are introduced deliberately as live food, or as a biological control for certain water conditions. As an example; many ponders specifically introduce Daphnia magna to their ponds to keep the single celled algae levels minimized (see below).
Many aquatic invertebrates produce copious amounts of eggs that can hitch a ride on anything from wind blown water droplets to insects. Once in your tank, or pond most do no harm at all -- if they are not too numerous. To identify what type of worm (or more likely type_s_ of worm) that is inhabiting your tank you need to look closely at the size, shape (if you can distinguish it), and swimming pattern of the worm. There are three major types of worms that are likely to be found in your tank water -- flat worms, round worms, and oligochaetes (the later group includes earthworms and a group of related, mostly freshwater, species of annelids). There are also other organisms that are small and thin and can easily be mistaken for a worm -- Hydra is a common example. Anyone who is interested in identifying a critter that is not listed here should put one in 70% alcohol for 24 hours, then put it on a piece of white paper and fold the paper over. Put the folded paper in a plastic ziplock bag, zip it shut, and mail it to the address below. Or, take a picture of one or more of them. If you can't photograph them draw a simple picture -- or both. Try to put the size scale into the photo or picture -- take a picture of it/them. If you can't photograph them, then draw a simple picture -- or both. Try to put the size scale into the photo or picture -- either draw it in by hand or use a ruler in the photo.
Once you have a picture scan it into your computer and post it on the web -- WAIT, we realize that many people do not have a scanner. We also realize that many people do not have their own site that can be accessed from the web. However, we suggest this because a picture is worth a gigabyte of ASCII. In addition, we do not allow downloading of ANY files sent to us electronically, so a picture posted on the web is the only kind we will look at. It is also a good way of avoiding obnoxious stuff.
We realize that the question (What is this bug -- insect lava -- critter?) comes up all the time. So we will to do the following: If you snailmail the picture or photo to us at the post office box address below we will scan it, put the scan on this site, and see if we or someone else can identify it. We will then post the identification and -- if the sender has included his/her e-mail address with the photo, we will post a reply directly back to them (If you do send you e-mail address we will _NEVER_ sell it, give it away, or release it for any reason).
Send pictures to:
LarvaTech
Critter Photos
P.O. Box 641541
Los Angeles, CA 90064-1541
What you get:
Identification of your critter.
What we get:
A better informed fish keeper who is more willing to feed live food.
Often the fish keeper suddenly realizes there are "millions of things" swimming around in his/her tank or pond and their initial gut reaction is KILLLLL ITTTTTT! They quickly run out and buy an antibiotic or other biocide. What we here at LarvaTech would like you to realize is that the bio-diversity in you tank in fact helps stabilize the tank/pond environment. We encourage you to contemplate not getting rid of (poisoning) all of them completely. We suggest this for the simple reason that species diversity in your tanks provides the same balance that it does in the wild. That is, it _buffers_ and prevents large swings in water conditions. It is very likely that if your tank has been cycled, these organisms are already present. What has likely happened is that the organisms were there all along and that you just noticed them. Or there has been an increase in the food available to them and their population has increased dramatically. What would be the best approach to controlling them is to learn what they are, find out what they are eating, and decrease the abundance of this item.
Flat Worms
One common critter is a tiny white "worm" that seems to glide around on the water surface and sides of the tank. These organisms are Planaria (commonly called flat worms). Some species of flat worm can be very tiny -- almost microscopic. All Planaria glide on cilia and slide (some say like a snail or slug) along surfaces such as the glass sides. They can glide on the glass front of your tank and do in fact glide across the underneath surface of the water using the water's surface tension. Planaria are sometimes incorrectly confused with microworms. (Microworms are an excellent food for fish fry).
The distinction between planaria and microworms is easy to see. Although microworms and the small planaria are similar in size, microworms cannot move along a flat surface under water. They flex from side to side and cannot swim or glide on a surface that is submerged.
Planaria in general are harmless, usually appearing in large numbers only when large amounts of food are present. In aquariums, food typically consists of excess fish food due to over-feeding. There are several freshwater and marine forms. Some of the marine forms can get quite large. Larger freshwater species are themselves eaten, in some cases, by certain types of fish. One of the most common of the larger freshwater species (and used frequently in Biology classes) is Dugesia. Dugesia can reach a length of slightly over a centimeter long and is further characterized by having an arrow shaped head and a grayish color, not white.
Kingdom: Animalia
Phylum: Platyhelminthes
Class: Turbellaria
Order: Order Tricladida
Photo of a typical small aquarium flatworm picture 1
Photo of a typical small aquarium flatworm picture 2
Microworms
Microworms are near microscopic roundworms. They belong to the phylum Aschelminthes and the class Nematoda (roundworms). Roundworms in general are interesting from a biological perspective. Inhabiting virtually every conceivable earthly niche the number of species is staggering. One study found approximately 90,000 individual nematodes in a rotting apple. Another reported 236 species living in several cubic inches of mud. Described species are over half a million. It has been estimated that if all the material on the earth except for round worms were to disappear the ghost of everything, (plants [including trees and many agricultural crops], rocks [yes rocks!], soil, animals [including we humans]) would still be visible, due to the clouds of roundworms living on and around us. Roundworms are also interesting because they lack a true coelom (gut or intestine) and are thus classed as pseudocoelomates. Developmentally the tissue that makes up the lining of the intestine is not entirely of mesodermal origin and hence the difference from true coelomates. The bodies of roundworms are bilaterally symmetrical and protected by a tough cuticle. They have two main muscle groups on each side of their bodies and swim by flexing first one side and then the other. Many roundworms, including microworms, therefore swim with a characteristic "s" shaped wiggling (See the photomicrographs on our Homepage and below). In addition, most roundworms including microworms have no organized circulatory or respiratory systems. However they do possess nerve and muscle systems. Males use special spines to inject sperm into the females' reproductive tracts. The sperm actually lack flagella and move by pseudopodia, like amoebas. Microworms pose no threat to any multicellular organism. They prey only on microscopic organisms such as yeast. The food particles ( yeast), are collected in the pharynx and macerated there by a series of radially oriented muscles. The crushed food is then passed on to the gut or intestinal tract, broken down by digestive enzymes, and assimilated. In water microworms swim in an "S" shaped wiggling manner. Microworms grow in distinct stages. Stage one is the smallest or youngest of these stages and about 80 uM long by about 10 uM in diameter. A size that is almost invisible to the human eye. The largest of the stages is about a millimeter in length with a diameter of about 60 uM. Even the largest forms can be seen easily only with some magnification.
Can I order a culture?
Kingdom: Animalia
Phylum: Aschelminthes
Class: Nematoda
Tubifex
Primarily sold as a live food, tubifex worms are very often and very incorrectly called, or sold as, bloodworms or blackworms. Tubifex have a reputation for bringing various diseases along with them to your aquatic system. This reputation (deserved or not) may be the reason many local pet shops now call them something - ANYthing else. They are brownish - reddish worms 1-2 inches long and more slender than blackworms and have no easily visible segmentation. Often seen in pet stores as a dense brown/red mat or blob with a slimy appearance. They must be kept in cold water and are generally stored by pet stores in a refrigerator. In nature they are generally found in sewage, or water with a heavy organic load. They live submerged, in burrows, and often wave one end in the water to feed. More than 50 species have been described.
Kingdom: Animalia
Phylum: Annelida
Class: Oligochaeta
Order: Microdriles
Family: Tubificidae
No photo yet.
Blackworms
These worms are a freshwater Annelid of the Class Oligochaeta. The oligochaetes include earthworms and a group of related, mostly freshwater, species of annelids. Over 3000 species are known. Oligochaetes all bear setae (small hairs on their sides that help "ratchet" them through the soil), but the number of setae present is much smaller than in polychaetes (their name (Oligochaeta) means "few hairs"). Black worms (Lumbriculus variegatus) are also known as a California blackworms, or mudworms and are members of a small subgroup of oligochaetes that are not earthworms or tubifex. About 3 - 4 inches in length when relaxed, and on the reddish side (usually a brighter red than tubifex despite their name). Blackworms are found in the sediments of North American ponds and lakes. They do not like light, are thicker and more earthworm-like than tubifex, coil and thrash like redworms when caught, and do not form the slimy blobs common to tubifex when kept confined in large numbers.
Kingdom: Animalia
Phylum: Annelida
Class: Oligochaeta
Order: Lumbriculida
Photo of a blackworm
Second photo of a blackworm
Whiteworms
Whiteworms are also Annelida, of the Class Oligochaeta (see above). Adult Whiteworms are slightly over an inch long (more that 4X the size of a baby guppy) and in general are too large to feed baby guppies. Whiteworms are terrestrial and can be cultured as a live food by aquarium hobbyists in potting soil. They are somewhat harder to raise than Grindals. The main reason is that they do not like warm (Above 70F) temperatures. If the temperature of the culture is allowed to remain above 70F for more that a day or two the yield quickly decreases. There is one report that putting them in a refrigerator is a way to keep the culture going in the summer months and we here at LarvaTech are currently testing several methods along this line.
Can I order a culture?
Kingdom: Animalia
Phylum: Annelida
Class: Oligochaeta
Order: Haplotaxida
Family: Enchytraeidae
Photo of a Whiteworm
Grindal worms
Very little is known about the physiology of Grindal worms. They are a small white terrestrial worm around 1/4" and at most 1/2" in length. They are thinner than Whiteworms of the same length. Information as to Class, Order, and even Phylum is obscure.
Grindal worms are cultured by aquarium hobbyists as an excellent food for young fish. They are cultured in potting soil similarly to Whiteworms, but prefer higher temperatures.
Can I order a culture?
Kingdom: Animalia
Phylum: Probably Annelida
Photo of a Grindal worm
Water fleas -or- Daphnia
Daphnia are common in aquatic systems particularly in outside ponds. Although they may look like small insects, Daphnia and Cyclops (see below) are actually crustaceans. Crustaceans have exoskeletons like insects-- that is they have their skeletons on the outsides of their body. Daphnia are members of the Branchiopoda. Most Branchiopoda are small and segmented like miniature shrimp. Daphnia however, while small, some are about the size of a period, resemble a miniature clam with two prominent halves. Two branched arms protrude from the top of the "clam" . These "arms" both propel the organism and filter small organisms and organic material from the water. Many ponders specifically introduce Daphnia magna to their ponds to keep the single celled algae levels minimized. We believe that this is the best way to treat this type of algae problem and discourage the use of algaecides in outside pools. For more information about adding daphnia to a pond to control green water see our Daphnia page. Although their common name (Water fleas) conjures up the image of the animal "jumping" or "hopping" through the water, in reality the animals swim with a smooth scurrying or bobbing motion from resting point to resting point. If there is something that "jumps" along the surface of the water it is most likely cyclops (see below). Most aquarium specialists believe that daphnia are excellent food for young and adult fish. They are easily cultured in old aquarium water.
Can I order a culture?
Kingdom: Animalia
Phylum: Arthropoda
Subphylum: Crustacea
Class Branchiopoda
Order Cladocera
Family Daphniidae
For photographs of different types of daphnia.
Cyclops
Cyclops are freshwater crustaceans like daphnia (see above). However their mode of locomotion is far different. Cyclops move in leaps and jumps across the surface of the water and they often stop or rest at the surface. Daphnia on the other hand rarely if ever stop swimming when they do not have anything to cling to. Cyclops have a reputation for damaging the eggs of tropical fish and of not being a very good food source for fish fry.
Kingdom: Animalia
Phylum: Arthropoda
Subphylum: Crustacea
Class Branchiopoda
Order Copepod
Photo of a Cyclops
Scuds - Gammarus- sideswimmers
A scud looks something like a miniature shrimp. Some species reportedly grow to be close to an inch long but the ones used in aquariums as live food are smaller than that - slightly longer than 3/8ths of an inch. They can walk both in and on the detritus that accumulates at the bottom of lakes, streams, and other bodies of water (There are salt water forms too). They can also walk on land but they rapidly dry out and die. Scuds are strong swimmers and zip away at top speed when disturbed often swimming on their sides and are thus nicknamed sideswimmers. Scuds are scavengers and will attack and eat decaying plant material but if not overcrowded will not harm healthy aquarium plants. They feed similarly to shrimp and crabs by scraping material off surfaces and/or filtering small particles with bristle covered limbs from the water.
Kingdom: Animalia
Phylum: Arthropoda
Subphylum: Crustacea
Class: Amphipoda
Order: Gammaridae
Family: Gammarus
For photographs and more information on scuds.
Bloodworms
These are a larvae of a fly or midge, they are not true worms. They are about 1/4 of an inch long and about the same thickness as a Whiteworm about 1/16 of an inch. Bloodworms live in water that is often low in oxygen and thus use hemoglobin (similar to that in our own blood) to collect as much oxygen from the water as possible. Because of the red color of hemoglobin the larvae are bright red (Really bright -- the color of the reddest apple you have ever seen) and appropriately called blood worms. Although they have an exoskeleton and small clawed legs, the larvae will often build a small tube of debris around themselves for camouflage and protection from predators. Adults are related to mosquitoes and often fly around bodies of water where they mate and lay eggs.
Kingdom: Animalia
Phylum: Phylum Arthropoda
Class Insecta
Order Diptera—the two-winged flies
Suborder- Nematocera
Family -Chironomidae
Photo of Bloodworms
Glassworms
Glassworms are similar to blood worms in that they are not a worm. They are the larval stage of a large gnat. They are usually only available seasonally and are caught "wild" which can introduce disease into your tank or pond. They are about 1 inch long and about 1/4 of an inch thick. Glassworms live in open surface water unlike bloodworms. They are clear and internal organs are easily seen. They generally hover or float in one location but can move very rapidly by sudden flexing of their bodies. Adults are related to mosquitoes and often fly around bodies of water where they mate and lay eggs.
Kingdom: Animalia
Phylum: Phylum Arthropoda
Class Insecta
Order Diptera—the two-winged flies
Photo unavailable
Mosquito Larvae
These aquatic larvae grow up to be mosquitoes. Which can carry a variety of blood born illnesses for humans as well as pets. Not a good idea to let them grow into the winged adults.
Kingdom: Animalia
Phylum: Phylum Arthropoda
Class: Insecta
Order: Diptera—the two-winged flies
Suborder: Nematocera
Family: Culicidae
Photo of Mosquito larvae
Mosquito larvae 2
Crane fly
Very often confused with a HUGE mosquito -- which is the only reason I put them on this list. The adults look like a 2inch mosquito with long legs. Their larvae are terrestrial and feed on the roots of grasses.
Kingdom: Animalia
Phylum: Phylum Arthropoda
Class Insecta
Order: Diptera—the two-winged flies
Family: tipulidae
Cranefly photo
Cranefly 2
Dragonfly larva
Depending on the species they will eat a fish as large as an adult tetra.
Kingdom: Animalia
Phylum: Phylum Arthropoda
Class Insecta
Order: Odonata
Suborder: Anisoptera (Dragonflies)
No photo yet.
Hydra
A small, tentacled, carnivorous organism closely related to corals and jellyfish. Gouromies are reported to eat them. Most adult aquarium fish are too large to be bothered by them.
- "Hydra, which is used in many textbooks to illustrate the phylum, is utterly atypical: a hydrozoan, it lacks a medusa, it has
aggregations of gametogenic tissue that function as gonads, and it is among only a handful of freshwater cnidarian species." -- Discussion of Phylogenetic Relationships -- (WEB) Page copyright © 1997 Daphne Fautin and Sandra Romano.
Kingdom: Animalia
Phylum: Cnidaria
Class: Hydrozoa
No photo yet.
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