Water Hoglouse

Asellus aquaticus

''Asellus aquaticus'' is a freshwater crustacean resembling a woodlouse. It is known by common names including "waterlouse", "aquatic sowbug" and "water hoglouse".
Water Slater (Asellus aquaticus) I check and maintain my pond at home most days, and rarely see these bottom feeders, so they immediately attracted my attention.

As I note in the accompanying video, I suspect they were feeding on a dead frog (a possible concern in itself) which drew them closer to the surface.

The photo is a little hazy as it's taken through a couple of inches of daytime water, but luckily the video gives a clearer view, and further information on this pond dweller: 

https://www.youtube.com/watch?v=taFMbnneItY Asellus aquaticus,Geotagged,United Kingdom

Status

A number of subspecies are considered to be endangered including:
⤷ ''Asellus aquaticus carniolicus'', endemic to Slovenia.
⤷ ''Asellus aquaticus cavernicolus'' found only in Italy and Slovenia.
⤷ ''Asellus aquaticus cyclobranchialis'', endemic to Slovenia.

Habitat

Known as "cress bugs" to anglers, ''Asellus aquaticus'' is common throughout the temperate zone including Europe, Russia, and North America. It is found in rivers, streams and standing water particularly where there are plenty of stones under which it hides although not where the water is strongly acidic. It is a detritivore.

''Asellus aquaticus'' is relatively tolerant of a range of pollutants and has been used as an indicator of water quality.

Reproduction

'Asellus aquaticus' can breed throughout the year, if the temperature is high enough: they do not breed under cold temperatures. Maturity can be reached in few months under warm summer temperatures, but maturation may take as much as two years in permanently cold water bodies . Life span varies similarly: from 9 months in South Africa to 20 months in Northern Europe. Females carry eggs in brood pouches underneath their body.

References:

Some text fragments are auto parsed from Wikipedia.

Taxonomy
KingdomAnimalia
DivisionArthropoda
ClassMalacostraca
OrderIsopoda
FamilyAsellidae
GenusAsellus
SpeciesA. aquaticus
Photographed in
United Kingdom