#crayfishes

[ichneumoniid]

Beast that goes 🥺

[aquariuminfobureau]

A lot of people are paranoid about keeping crayfishes with fish. I think the problem is based on misunderstandings about crayfish ecology and behavior. Crayfish themselves happen to confuse many people, for example,as to wether they are lobsters or not: semantically, the word 'cray' is a cognate of 'crab', and the word 'fish' was used historically (and in fisheries, up till the present) to denote many animals associated with water. Crayfish or crays are, however, not actually crabs in the modern sense of that word. Also depending on the dialect of English, words like 'crawfish' can apply also to certain marine lobsters and burrowing, estuarine mud shrimp, although they are undeniably cognates of 'crayfish'.

English as a language is very confused as to its 'cray' and 'craw-', and it is naturalists and zoologists who first attempted to standardize a certain use as particularly 'proper' across dialects. But, in any case, the root is probably from an old Indo-European root, meaning to scratch or crawl. Less possible is a relationship to the word 'scarab', from a Greek word that refers to scorpions, and of course large beetles, as well as crabs and lobsters; this word entered Greek early from a Semitic language in which it had meant 'scorpion', but the English use it today, in reference to a kind of dung beetle.

Although people will insist that crayfishes are not lobsters, crayfish are in fact s freshwater subclade of the lobsters, that evolved adaptations to consuming vegetable material as live plants and detritus; crayfish do also consume animal carrion on slow moving prey, although the exact proportions of the items in their diets varies by the species, and by such environmental situations as are determined by the season of the year. From this it may be determined that none of the crayfishes are active predators, being rather omnivorous foragers; in fact they obtain animal protein through the chemosensory cues that are specific to carrion, or by cues of touch as they go along. It is not unusual for plant eating crustaceans to consume meat opportunistically, and even preferentially when it is available But this is because the opportunity is rare, and their diets suffer deficiencies in some kinds of nutrients. Crayfish should in fact have a plant based diet in the aquarium, for the most part, and foods of animal origin should be but a supplement provided.

Now, people regularly confuse gestures of aggression by crayfish, with predatory intent. It isn't the same thing at all, though agonistic encounters can turn violent. Such hostility is related to competition for the use of available space, and bottom living fishes are the most likely to irritate a crayfish Especially those kinds of fish that hide in the same sort of locations that crayfish are disposed to utilize as a retreat. Crayfish can not only be hostile towards fish in this way, but also to one another, which some people think is related to a cannibalistic intent. But when crayfish are cannibalistic, it is a larger cray preying on a smaller individual, whilst it is molting - a process that leave a young crayfish temporarily without defence, and vulnerable to attack.

From this it can be seen that animals that do not compete with the crayfish for space, or threaten it as a predator, will be safe. Obviously this does not apply to slow moving animals such as snails, and sleeping fish are also vulnerable. Although some people cohabit small, dither-type aquarium fish with crayfish, there will always be a risk if these little fish are caught unaware. I do not condone this and I insist that all tankmates should be robust and suitably large - commonly this is expressed with reference to the length of the crayfish itself, or the size of its pincers combined. Obviously all tankmates for a crayfish must favor the same parameters in which the crayfish will thrive: so for example, the popular North American swamp crayfishes (Procambarus sp ) cohabit well with goldfishes, because they originated in similar environments, although on different continents.

It is sometimes said that the Australasian or Australo-Papuan crayfishes (Cherax sp.) are the least dangerous crayfish to fishes. Whilst it is true (on the whole) that they are more placid than the North American swamp crayfishes, they can still kill fish, and one another. The same cautions should apply when cohabiting Australasian crays with fish, as with other crays; although at least half of the common misunderstanding, is the mistaken belief that other types of crayfish are violent predators. The genus Cherax are those that also known as yabbies, especially in Australian English. As with some other colloquialisms, like 'goanna' for the local monitor lizards, it corresponds to a natural group of Australasian animals, so it is pointless to say that all crayfish are yabbies; though again, Aussies themselves also use the word 'yabby' to refer to some unrelated, saltwater crustaceans

Another kind of crayfish that is sometimes advocated for fish aquariums, is a selectively bred morph of a small, Mexican crayfish species (Cambarellus patzcuarensis). In this case it is the diminutive size of the cray that limits it's ability to damage other animals, but it still consumes snails and, at least in anecdotes, very small and unwary fishes. I am unaware of any other crayfish species currently being traded in Europe, but formerly the signal crayfish (Pacifastacus leniusculus) was widely retailed for life in outdoor ponds. This temperate climate species was considered as a friendly scavenger, but was soon realized by many that they consume underwater plants - this is the natural role of crayfish! - and less accurately, they also came to be blamed for the unobserved deaths of fishes that they scavenged, as is also their nature. Most signal crays did no harm to pond fish at all, but misunderstandings of their behavior led many people to be paranoid of keeping crayfish in ponds and aquariums.

[ameenullasamg]

Took some shots of my #crawfish #crawfishes #crayfish #crayfishes #lobster #lobsters https://www.instagram.com/p/CgMdzT8hw65/?igshid=NGJjMDIxMWI=

[aquabonsai]

Another photo of the new color morph pink clarkii #crayfishes #aquarium #crustacean #lobster #aquariumfish #crab #freshwater #freshwatershrimp #freshwateraquarium #cichlid #tetra #astacology #procambarus #fishtank #pet #fish #china #taiwan #australia #newyork #germany #korean #japanese #cambodian