The Bluelined Shrimp goby (Cryptocentrus fasciatus) which was first described by Playfair in 1867 with the holotype being from Zanzibar, may be conspecific to Cryptocentrus fasciatus which was described in Australia in 1953 as the two resemble each other. Possibly only DNA testing may confirm this but at present Cryptocentrus fasciatus is considered an endemic species in Queensland, Australia. They are common in some areas of the Tanzanian coast. As their name implies they have a symbiotic relationship with species of alpheid shrimp.
The shrimp constructs a burrow in the sand and both parties live in the burrow. The goby acts as a guard for the shrimp which has poor eye sight. Both species gain protection and more from this relationship making it a true symbiotic relationship.
The Bluelined Shrimp goby has a proportionally elongated body and large eyes on the top of their head giving them a good field of vision. The base body colour is a light brown colour and there are several dark brown colored bars on the body. On most specimens there is a light brown patch on the head behind the eyes.
The face has blue speckles on it extending back onto the gill covers and the pectoral and pelvic fins are speckled in yellow and blue dots. The anal fins have blue lines on them giving the fish its name. The pectoral and pelvic fins are well developed and the fish use these to perch on. They grow up to 10 cm in length in Tanzanian waters.
BLUELINED SHRIMP GOBY IN THE WILD
There seems to be little literature on this particular species of Goby. In Tanzanian waters they are common in silty protected areas from 5 meters downwards to at least 10 meters. They are shy fish and are quick to dart into their burrows.
The best way to observe these fascinating fish in the wild is late in the afternoon just before dark. If one approaches the burrows very carefully and doesn’t breathe out too hard, with a camera with video lights on it the fish seem to ignore one.
The fish and the shrimp remain in physical contact with each other for most of the time, with the gobies tail almost constantly in touch with the shrimp. If one moves while the shrimp is out the burrow the gobies gives its tail a fast flick and both shoot down the burrow at quite some speed. If one waits the goby will eventually stick its head out the burrow and when it feels safe will partially emerge again.
OTHER INTERESTING FACTS AND OBSERVATIONS
At times both the shrimp and the goby leave the burrow together to search for food staying in close contact with each other. The fish have also been observed taking food back to the burrow for the shrimp and the two species have a complex inter relationship which is mutually beneficial for both parties. The burrows have been found to be up to two feet long, having numerous branches.
While the size of the burrow seems to correlate with the size of the shrimp, the size of its partner goby does not necessarily go along with the size of the goby. We have observed large shrimp with small gobies.
The Bluelined Shrimp goby is found across the Indo west Pacific area from East Africa to Southern Japan, south to the Great Barrier Reef. They seem more common in silty areas.
The Bluelined Shrimp goby feed on planktonic matter passing by their burrows. They have also been observed leaving their burrows and feeding on benthic organisms in the sea grass.
Mating takes place in a side corridor off the main burrow and the eggs are guarded in the side burrow by the male. The eggs hatch at night and the larvae exit the burrow, becoming planktonic.
Bluelined Shrimp goby can be kept in aquariums but generally more colorful species of Shrimp gobies are kept in aquariums. If more than one is being kept then it is best to have a mated pair as the same sex gobies may fight.
BLUELINED SHRIMP GOBY CLASSIFICATION
- Bray, D.J. 2017, Cryptocentrus bulbiceps in Fishes of Australia, accessed 11 Dec 2018, http://fishesofaustralia.net.au/home/species/96
- Assistance from Elaine Heemstra