Quote:
Originally posted by TimBeR
Today I was at a Local LFS and came across a Beatiful BLue Linka Star. I held of on buying it because I know nothing of their requirements and or if they are reefsafe and will they be ok with a black banded serpent star in the same tank... ...would be in my 29 gall setup for about 2 or 3 months at least ...
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These are beautiful and intriguing little creatures, the comment about them being very low on the evolutionary scale is correct. They are biofilm and detritus feeders, and would not compete with your serpent star for nutrition. The biggest problem I would see with your tank is its size, as each specimen of
Linckia levegata would most likely need at least 5 to 6 square feet of bottom and rock substrate space in order to feed adequately. Another more serious problem relates to the stability of your salinity in such a small tank. Although evaporation-related swings in salinity are quite gradual, many of the replenishment (top-off) methods are not. Especially with a small tank, you will need to replace your evaporative losses as they occur in order for your salinities to remain at the steady concentration needed to maintain these creatures. Salinity needs to be at 35 PPT and stay there. These beauties are quite long lived if they are collected and shipped correctly and acclimatized very slowly to match your tank's conditions.
I see a lot of questions about these wonderful little creatures that ask specifically about acclimatization and the low survival rate of specimens. The fact that Linckia stars have an 80 to 90% mortality shipping rate is most likely due to the improper acclimatization of the sea stars, not necessarily the shipping itself, although this acclimatization problem can occur when the specimens are transferred to holding tanks by any number of intermediate stops in the shipping process. If your sea stars get small white ulcerated "puffs" of tissue, then seem to explode, it is prolly due to the acclimatization problems seen with these echinoderms.
One of the features that distinguish echinoderms from all other animals is the presence of the ambulacral system, a relatively high-pressure hydraulic system that is used to power Asteroidea body movements. This hydrovascular system is a set of vascular vessels that use body fluids and seawater to extend and contract their tube feet. Tube feet are extensions of the final branches of this hydrovascular system. Although is was long thought that the tube feet used the hydrovascular system to produce suction that allowed the tube feet to “grab” the substrate, etc., it is now known that the base of the tube feet use a 2 substance system of adhesive/adhesive-resolver to literally “glue” the tube feet to the objects they come in contact with and unglue them to release them.
The presence of the hydrovascular system is probably one of the major limitations for keeping Asteroidea in the home aquarium. The ambulacral system is made up of many membranes and delicate tissues that simply do not respond well to repeated challenges by fluctuations in the salinity of the environment. If the changes are abrupt enough, the tissues/membranes will respond by rupturing due to the osmotic gradient across these membranes. Most echinoderms simply cannot tolerate fluctuations in the salinity of the water column. Echinoderms are some of the oldest living extant spp. of marine creatures, and have over millions of years adapted to living in fully marine (as opposed to estuary or brackish or freshwater) conditions, with the salinity at 35 to 36 PPT (1.026 S.G.at 84° F). Water does not enter the water vascular system passively; rather, it is actively pumped into the hydrovascular system through an as yet incompletely understood metabolic pathway. Fluctuations in salinity of the water column result in ruptures in the membranes of the hydrovascular system. This often leads to the ultimate death or at least the “explosion” of the sea star. This demise often occurs over several days to weeks, with pieces of flesh falling off the main body mass after the damage to the ambulacral system has occurred. See
http://www.geocities.com/banggai/blinckia.html for some pictures of the effects of salinity swings and poor acclimatization methodology on
Linckia levegata. Some times the remaining rays will re-grow the central disk, so it is possible to maintain the pieces to recover and re-grow full bodies if there are few scavengers… most often though the sea star never recovers.
In addition to the possible assault on the hydrovascular system, Linckias have another target of salinity weaknesses. The aboral surface of stars is often covered with small, delicate, filmy projections of the main body cavity of the creature through holes in the body wall. These are the dermal gills, considered to be the primary site of gas exchange. These projections are filled with fluid from the body cavity, which is circulated through the structures by cilia. These dermal gills are also subject to osmotic rupture and damage during periods of salinity fluctuation. Consequently, although sea stars can survive a wide number of environmental challenges, from poor water quality to temperature fluctuations, they simply cannot tolerate fluctuations of salinity. Handling these creatures may damage these dermal gills as well, so the physical manipulation and relocation of these creatures should be discouraged.
I wish that I could tell you that I have had fantastic success using the following acclimatization procedure, but often prior handling of the sea stars will determine how well they will survive in your tank. Remember that the damage to the hydrovascular system is often slow to appear in the creature. Make sure that when you select your sea star that you look for firm creatures with no strictures or pits on the dermal surfaces and well-extended tube feet on the aboral surface of the rays.
The best method of acclimatizing these wonderful creatures is to arrange a drip (get an IV tube set from the hospital if possible) and place the creature in a bucket or container large enough to hold the sea star and it’s water that it was shipped in. Place this container in another container (PLEASE, NOT the SUMP!!! This allows the introduction of the shipping water and anything else in that water into your system… …including copper…) large enough to hold 4 volumes of the first container (or use a sink). Start the drip at about 1 to 2 drops per second, and remove approximately 1/3 the volume of the container every hour. This will take about 4 to 6 hours to equalize the volume, depending on how much water you start with. I would suggest this method whenever introducing ANY echinoderm, and prolly snails as well, although most marine snails will do with a 2 hour acclimatization. If you can’t acquire an IV set from the hospital, take some
air line tubing and put a clamp on the tube to adjust the flow rate into the acclimatization chamber. The above mentioned plastic air valve would work as well, or tying a knot in a length of air hose will do, just adjust the drip rate by tightening the know (check this often, as the rate will change as the plastic "relaxes"). Use a watch to see how many drops fall in to the container in 30 seconds (use this as 25 to 50 drops per 30 seconds).
I hope this helps, I have lost a few Linckia over the years by not knowing this information. I know that most of the info here is specific to Linckia spp., but it applies to ALL echinoderms as well, urchins, sea cukes, sand dollars, and sea stars, although the Linckia spp. seem to be the most susceptible.
Sorry for the long post. Hope this helps.
