About animals

Marine invertebrates


One of the most unusual inhabitants of the aquarium can rightfully be considered a sea urchin. These animals are often compared to ordinary hedgehogs, as many subspecies have similar needles.
Most species of hedgehogs are safe for humans. You can pick them up without any risk of pricking or damaging your hand in some way.

The body shape of all types of sea urchins is similar - it is a chitinous carapace of small plates that are connected together immovably. The mouth is located on the ventral side of the animal. It should be noted that this side is always directed to the bottom. Several legs extend from each of the plates, with the help of which the animal can crawl or attach to substrates. The number of such legs can even reach thousands.

Sea urchin needles

On the carapace of the animal there are also various tubercles on which needles are attached. They are different in appearance and size. There are hedgehogs whose needles are much larger than the body of an animal. They are used mainly for protection, less often, as a possibility of movement.

Hedgehog needles contain toxic poison, causing serious damage to marine life. In this case, the poison can poison the surrounding inhabitants, even if it is soluble in water in large quantities.

For humans, hedgehogs also pose some danger. So, when injected, the particles of the needle remain in the victim’s body, which causes muscle paralysis and disruption of the nervous system. Therefore, if you take a hedgehog in your hands, although you can do without it, be extremely careful.

Aquarium Maintenance

Although the hedgehogs are free to reach sizes up to 20 centimeters in diameter, they do not grow much in the aquarium.
Hedgehogs feed mainly on blue, red and brown algae. Animals bring great benefits to the aquarium by eating various formations on stones, glass and soil.
When making an aquarium, you should take into account that you will need to securely fix all the decorations, as these small animals can shift their weight by more than 50 times.

Sea urchin is an unusual and beautiful inhabitant of the aquarium, but at the same time dangerous. Therefore, before buying such an animal, think carefully about whether you need it or whether it is better to do without a purchase.


Invertebrates are a large group of animals deprived of the spine. It has more than a million species, a variety of forms - from sponges to insects. Invertebrates include protozoa, sponges, coelenterates, lower worms, mollusks, arthropods, echinoderms, and others. Invertebrates are ubiquitous - in fresh waters, in the seas and oceans, on land, in the soil, many are parasites of animals and plants. Along with useful invertebrates, there are many harmful ones: carriers of pathogens of infectious and parasitic diseases, intermediate hosts of parasitic worms and carriers of vector-borne diseases, poisonous animals, pests. Most invertebrates living in marine aquariums come from the coral reefs of tropical seas. This is primarily about the corals and sea anemones themselves, but sponges, sea urchins, starfish, shrimp and shellfish are also widespread.

Snails, gastropods

The most common representatives of invertebrates in aquariums are gastropods, in particular snails. Being the most numerous and diverse class of mollusks, snails have a spiral-twisted shell, in which, in case of danger, they draw their head and leg. For the most part, these are unpretentious creatures that do not require special conditions of detention.


In addition to snails, all kinds of crustaceans such as shrimp, crayfish and crabs are very common in aquariums. The richness of the shapes and colors of these animals competes with that of fish. Most crustaceans are very sensitive to cleanliness and water quality. There are herbivorous and predatory species, but for the most part it is the so-called. “Filtrators”, that is, species that feed on organic remains that settle on the bottom.

Coral polyps

Coral polyps deserve special mention. These amazing invertebrates from the tropical seas are the "authors" of one of the most beautiful natural phenomena - coral reefs. Coral reefs are formed from the remains of limestone skeletons of polyps, and the skeleton of coral polyps can be both external and internal. In the upper body they have a mouth, bordered by a series of radially symmetrical tentacles, which are used to capture food.

Conditions of detention

The maintenance of invertebrates in an aquarium is often associated with many difficulties - it is necessary to take into account water parameters, the proximity to other representatives of flora and fauna, many species of invertebrates impose strict requirements on their diet. However, the beautiful appearance and incomparable pleasure received from observing these amazing representatives of the animal world more than pays for all difficulties. Moreover, many species of invertebrates contribute to maintaining the ecological balance of the aquarium - for example, crayfish and mollusks serve as a good indicator of aquarium contamination, some species are natural “cleaners”, eating organic remains of plants and fish.

General recommendations for the maintenance of marine invertebrates

Currently, a very large number of species of these beautiful animals are found in the aquarium. In addition, they have a striking appearance, unique behavior and interaction among themselves. However, it should be borne in mind that invertebrates are more whimsical creatures than fish. You should not start populating a saltwater aquarium with these animals. The overwhelming majority of them require a well-matured and well-equipped complex with a minimal amount of nitrates and phosphates. They also do not tolerate copper compounds. Of the equipment, a powerful foam separator, a good filtration system, and a carefully selected flow system are required. Many of them are photosynthesizing and have special requirements for lighting sources, such as sea anemones and corals, so special lights with the correct spectrum are needed.

Some live in symbiosis with each other, while others, on the contrary, are not compatible, or are predators, and this also needs to be taken into account.

Experienced aquarists can easily choose their favorite species.
But if you do not have much experience in marine aquarium, then it is better to start with unpretentious species: pulsating xenia, pachyclavularia viridis, some types of sinularia and sarcophytons, zoanthus, watered, ricordea. The hermit crabs and ofiura are also not very whimsical. In any case, the specialists of our store will help you find the right animals and advise on their further maintenance. You can also purchase related products from us.

  • Coral Feed
  • Frozen Invertebrate Feed
  • Dry specialized feed
  • Sea salt for coral
  • Sea water
  • Pure osmotic water
  • Living reef stones
  • Biopellets
  • Antiphos
  • Tests for sea water
  • Artemia cysts

Anemones (sea anemones) and corals

Anemones and corals are characterized by being attached to a solid surface and staying on it. Both species of these invertebrates are popular among amateur aquarists, but require careful monitoring of water quality.

Anemone is much easier to maintain than corals, but they still need special care: the absence of nitrates and a large amount of oxygen in the water, good aeration and circulation in the aquarium. Anemones come in various colors: pink, green, purple, orange, yellow or white, depending on the color of the algae living in their tissues. Anemones are mobile and can move on the surface. When they find a place they like, they are fixed on it.

Mandarin fish (Synchiropus splendidus)

Tubular worms

Tubular worms have been found on coral reefs. They are known for building pipes around their soft bodies using various materials such as sand or shells; some release calcium carbonate into the water. Tubular worms take various forms, from straight to spiral, thereby decorating reefs in aquariums. Their feather-shaped colorful tentacles hang from the top of the reef and serve as both a respiratory organ and an esophagus. If the tubular worms are frightened by something, they pull the tentacles inward.

Tubular features are divided into two large families, Sabellidae and Serpulidae.

Crabs and Shrimps

Crab and shrimp are often kept in saltwater aquariums. They are called collectively - crustaceans. They are part of the arthropod family. They differ in the type of shell that is dumped during growth in exchange for a growing new one (you will need to equip many secluded corners in the aquarium where they can hide until a new shell grows). Hermit crabs, arrow crabs, boxer crabs, harlequin shrimp - these are the most affordable crustaceans. Before populating the aquarium with certain crustaceans, make sure that they do not eat each other.

Antopleura yellow (Anthopleura xanthogrammica)

Starfish and hedgehogs

Echinoderms include starfish and hedgehogs. Most echinoderms live at the bottom of the aquarium. Many of them feed on other invertebrates, such as corals and even each other, so you should very carefully choose echinoderms for your aquarium.

Starfish are compatible with most fish, but will eat bivalves and sea urchins. Sea urchins are difficult to maintain because they require perfect water quality. They also need a significant amount of food (they feed on algae). Before choosing the inhabitants of your marine aquarium, learn more about the features of their content. Make sure that you can provide them with everything you need, and that the new inhabitants will not damage your fish.

Credit: Portal Zooclub
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Madrepore corals

They have a calcium skeleton and are reef-forming corals. Over the millions of years of existence, madrepore corals have significantly worked on the appearance of an old Earth. The most sensitive aquarium organisms requiring the perfect quality and chemical composition of water. Therefore, by the time the madrepore corals are placed in the aquarium, the environment in the latter should be absolutely stable. In addition, this species of coral does not accept the neighborhood with a large number of fish. Individual polyps in different species can vary in size from 1-2 mm to 20 cm in diameter. Madrepore corals have chemical means of protection (“burn”) and can lead real “wars” among themselves, so when you settle in an aquarium, you should pre-calculate the presence of free space between corals taking into account their future growth.

Tubular corals

There are different colors, polyps are small - up to 1, 5 cm, and in the colony are interconnected, forming large swaying surfaces. Some - such as tubipora - have a tubular skeleton like a honeycomb, which can be pulled in when a danger occurs. Other types of skeleton do not exist at all.

Soft corals

The skeleton is represented by separate internal needles, so these corals can significantly change their volume depending on conditions. As a rule, they are highly branched and look like small underwater trees. Different species have different dependence on light, while in aquariums it is easier to contain photophilous species, since they do not need additional live food.

The most suitable "for beginners" corals. They have a dense structure and consist of small polyps that can be “drawn in” or “pulled out”. Under good conditions and a sufficient amount of the necessary trace elements can very quickly increase in size.