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Hydras :

Their arrival in the ferry.
In aquariums, hydras arrive in our tanks through stones, wood, plants and living food taken from nature. They can also be present in an already infected tank, hence the fact of being attentive when changing the arrangement of plants / decor.
In our tanks are real predators who capture the small shrimp a few days old to make a festive feast. However, hydras are harmless to adult shrimp as well as fish larger than half a centimeter.

How to avoid bringing hydras into your aquarium:
• For decorations such as roots and rocks, nothing better than boiling them. A temperature above 40 degrees is fatal to them.
• For plants, a bath in water saturated with CO2 (commercially available sparkling water) for about 12 hours will suffice to eradicate them.

Exterminate them.
If your bin is infested, I advise you not to use the previous solutions which would be fatal to the entire bin.
Other solutions exist:
- The use of salt: 0.4% for a week also destroys them but the plants generally do not appreciate this concentration too much.
- The use of a predator: some fish are crazy about hydras such as: Trichogaster Trichopterus or Macropodus opercularis, or asolene, but in hot water not for our axos.
- The use of oxfendazole: this treatment is safe for the shrimps and fish in our tanks but can affect some snails, zoe and aeglas less than a month old Oxfendazole is more than 93% effective on all major dog parasites including Dipylidium caninum and Trichuris vulpis. Its original galenic form (oral suspension to be mixed with food) and its high acceptance limit as much as possible the handling by the owner.

The doltheme comes in 3 formats:
DOLTHENE® 20 ml: contains 453 mg of oxfendazole
DOLTHENE® 50 ml: contains 1132.5 mg oxfendazole
DOLTHENE® 100 ml: contains 2265 mg of oxfendazole

Treatment for the aquarium hobby.
The ideal: 1 ml of Dolthene for 80 liter of water.
As the eggs may remain, it is advisable to repeat the operation 4 weeks later. During the treatment no water change should be made. On the other hand after the two treatments a water change of 50% is strongly recommended. Then filtration on activated carbon, during 4 to 5 days (beyond that the carbon releases the substances absorbed so no longer any interest.

NB: The data of the treatment are indicative. It worked for us, however neither the author nor the site can be held responsible for any problems.


They are small flatworms (unlike the leech) , of the Turbellaria class, generally scavengers, white-beige, pink, yellowish or light brown in color, which measure from 2 to 10 mm and move by crawling. Planarians move slowly over leaves and stones. They glide over the background, like slugs, unlike leeches which advance in spurts, like caterpillars. They are introduced at the same time as the plants and the decorations taken from nature and badly washed.
To avoid planaria, before putting catappa or oak leaves in the tank, put them in the microwave for about 1 minute. Or before introducing new plants in a tank, let them soak for 48 hours, to avoid polluting your tank. The planar traps are not very effective (at least the homemade ones you can try the commercial oneshere , indeed even if you manage to catch the adults, the eggs will remain in the aquarium while the dolthene kills the planarians. adults and eggs Dolthene is not lethal to snails, unlike no-planaria and Fluvermal.

How do you get rid of planarians?
Either by removing plants and axolotls, fish from your aquarium and raising the temperature to 34 degrees. Either by treating with
Dolthene :

treatment for one month, buy the one for dogs from 13 to 33kg, in pharmacies, day 1 - change 10 water, put dolthene in the aquarium at the rate of 0.5ml per 50l of water. Do not touch anything for 15 days. On the 15th day, change 10 water and start again with 0.5 ml of Dolthene for 50 l of water. and 15 days later (ie 30 days from the very start of the treatment: change the water and filter through charcoal to remove the last traces of the product.

Fluvermal outside the axolotls ferry! A harmful aution for snails and can kill certain juvenile shrimp). Some axolotls support this treatment badly (use another molecule better tolerated such as Dolthene). Fluvermal is found in pharmacies without a prescription 1 tablet for 20 liters of water. Crush well then dilute in a little aquarium water before introducing the product. 4 days later, change 40% of water then filter 4 days on charcoal.

Leeches are part of the same family as earthworms, (annelids). They are generally introduced into our aquariums via the introduction of plants, stones, etc. taken from the wild. When leeches are small they are difficult to spot in a piece of wood or on rocks. At their adult size they reach 4-5 cm. They attach themselves to the fish and bleed them. They lose weight, turn pale and die. The wounds appear as small round, red or white holes. (Some species also attack planorbes and small snails in the tank).

Leeches are also vectors of bacterial diseases. To spot them you have to observe the aquarium during the night with a flashlight and remove any that you see. They have a particular, undulating stroke. Unlike the gliding planar, it moves like a caterpillar, lifting the middle of the body which comes off forming a loop that does not touch the wall.

Most salt treatments, for example, only kill adults and not eggs. The eggs are oval, dark brown in color, and stuck in clusters at the base of plants or in the interstices of stones. The effective products are also toxic to fish. Be careful therefore during treatments that must be renewed after 3-4 weeks to kill the new generations. They are sensitive to levamisole , and die at doses of treatment for deworming discus (1ml of the 10% solution per 100l of water). Levamisole is a vermifuge for veterinary use, so you should consult this one to get it.

Dragonfly larva:

This larva is a predator that lives in ponds and feeds on tadpoles, tiny red worms and other larvae. They are quite large, measuring 3 to 6 cm, and have six legs. It remains as a larva for 1 to 3 years and moults to grow and change its envelope. She wears a mask formed by the lower lip and terminated by two hooks which allow to grip the preys. Catching it remains the only solution. it can be extremely fast ... Personally, I siphon them. Good luck.

The dytic:
The adult and the larva are formidable predators. The larva, a large carnivore, will first inject toxic and digestive saliva which liquefies its body, before sucking the contents of its victim with its powerful mandibles. The beetle larva is very voracious, it attacks other larvae, tadpoles and even newts.
The Dytique hunts and kills prey that is often much larger than itself! It does not hesitate to attack tadpoles or newts, sometimes even fish such as sticklebacks or young perch or any fish in our aquarium. It attacks very close to the gills, where they are most fragile !


Aselle ( Asellus aquaticus) is a species of crustacean (Malacostraca) that lives in fresh, low-current waters, devoid of pesticides provided they are rich in debris of organic matter (dead leaves in particular). As a bioindicator, it is not an indicator of water of as good quality as the gammara.
In optimal condition for them, asellae can or could reach locally very dense populations. They are - along with gammaria and daphnia - an important source of food for various carnivorous aquatic organisms.
Asaddles are increasingly known in aquarists for their effective role as detritivores. They are easily differentiated from the scallops because the asellae are more flattened and walk on the bottom, more than they swim, while the scallops often swim or move "sideways" and the body curled up in a rounded position (on the bottom or when they run away).
Size: the aselle grows all its life, by successive moults and it lives 1 to 2 years: the adult measures 8 mm to 15 mm long (depending on the region, the subspecies).
Asellae are very common in ponds, where they feed on decaying plants, or even on corpses that have fallen to the bottom. Indeed, the asellae are unable to consume the slightest living tissue. They are therefore precious, since they sort, on the same sheet for example, between the healthy part and the dead part, eating only what is needed and sparing the rest.

Hence the idea of some aquarists to use the plates in the tanks where they kept the fish eggs. The aselles hastened to make disappear the unfertilized eggs, dead, reached by the mold, and thus protected the others, alive, of any contamination always to be feared. The live eggs were even cleaned regularly of any fragments of detritus that fell in contact with them.
First of all because biodiversity is important and it is better to multiply species than to remove them ... but also because fish have an unfortunate tendency to like to devour asaddles! The adults sometimes manage, if the plantation is very dense, to survive. A little Java, Ceratophyllum or Najas moss, and you're done.
But the small aselles are often used as lunch by the fish, who prefer them to their elders.

Many pond enthusiasts have solved the problem by placing the asellae in a dedicated compartment of their filter, where they can perform their role of degrading detritus (dead leaves and others) while remaining safe from the appetite of the fish. . Of course, a few individuals escape and that's good. They will serve as living food and will sometimes even settle in the basin in discreet corners.

Why not think about a similar use in aquarium keeping? Asellae intervene just before the ostracods in the waste degradation chain, thus preparing the work of the bacteria in the filter and in the tank. I think we should think about biological filtration systems that would include these critters, allowing them to live and multiply in the shelter.

Asellae are not as prolific as other aquatic invertebrates. They only lay a few eggs (around 200 per clutch) at the last stage of their growth. But the little ones, carbon copies of adults, are armed to survive.
Why not reserve part of the decanter for them, or better yet, a container for them alone?

The grammar measures approximately 15 mm.
It is a freshwater shrimp. The head has 4 antennae and two faceted eyes. On the stomach, gills allow it to breathe. This crustacean feeds on dead plants and plankton. She lives in the shelter of the light under the stones or under the rubbish. Fish, and carnivorous insects love it.

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