Murder in my tank!

[yossaria]

I am new to the aquarium realm and I am looking for some advice. I have a 40 gallon tank that has been in operation since late December. Early on, I just had live rock. A few weeks later I added a yellow tail damsel, cleaner shrimp, sand sifting starfish, a blue leg hermit crab, 2 red leg hermit crabs and 6 turbo snails. Everyone got along swimmingly and aside for some hair algae and brown stuff growing on the glass (that the snails ate) the tank was problem free...
Last week I received some new life forms that I acclimated to the tank water as described. I purchased a fire shrimp, a sally lightfoot crab, a cleaner clam, a queen conch, a lawnmower blenny, and a yellow pygmy angelfish. I was hoping the blenny would mow down some of the algae but he has been a huge disappointment. The queen conch has been cool to watch and is happily scouring my aquarium glass. The damsel, blenny and angelfish have adapted to each other and the fire shrimp seems to be most happy when hiding (what a waste of 29 bucks). The most active animal by far is the sally lightfoot crab that arrived missing a leg (leg not in bag so it must have come to the vendor this way). The sally lightfoot is fun to watch and spends a lot of time cramming substrate into its mouth.
All was cool until I checked on the tank this morning and found my starfish dead in a corner with two mangled legs! I am assuming that one of the guys I introduced into the tank 2 days ago is to blame. I suspect that it is the sally lightfoot crab since I have witnessed it nipping at some of the other tank occupants. However I cannot prove this. Maybe sally is pissed off because some numbskull that catches these animals for sale pulled one of her legs off! I put the starfish under a microscope (I have a biochemistry lab) and observed several microscopic critters running around on the starfish. None of these critters could have possibly made off with a quater of a leg, but it is possible that they are parasites and weakened the starfish. Probably more likely they are just copepods. There also seemed to be some green slime like stuff at the site of the wound. I have no idea what this is.
So what do you think? Was it likely the sally lightfoot? Should I remove it from my tank to prevent further casulaties? Please share your experiencies.
Thanks for any help!
Yoss

 

[aquaria]

It sound like the Sally dident kill it, really what i think happened is that the starfish died randomly and the sally decided why let good potential food go to waste. :thinking:
This never happened to me like this, but i have heard other stories!

 

[ophiura]

Sand sifter stars need very very large tanks and even then tend to starve in about a year. The tank is far too small, and far too young, for any seastars.
Please provide your specific tank parameters. How did you cycle this tank?
Seastars are some of the most difficult animals to keep in our tanks. They are unforgiving in having any parameters off. In particular, if your specific gravity is less than 1.025, then it is too low.
It is very tempting to think our animals are perfectly healthy and are killed rather than the more likely answer...that they died for some reason.
These stars, when dying, disintegrate, losing large sections of their arms. As they die, many animals such as hermits or other scavengers may start eating them...they know it is dying and can smell it. They did not, however, kill the star.
This star probably died of a water parameter issue, IMO. Acclimation shock can often set in up to a month after introduction. It takes several months to starve, typically. But both are possible reasons for the loss but I am more confident of the acclimation issue.. Most of these stars will die in captivity.

 

[ophiura]

I also must very very strongly encourage you to slow down. IMO, the tank stocking is proceeding rather quickly (I know you may not believe this ), and does not appear to be 2 months old in total. Patience is critical in this hobby, and unfortunately, lack of it is the major reason people fail and leave. This is not to flame you in any way, but it happens all to often...a common story on these boards.
Your crab will regrow the leg. This is not a problem and is a common occurence in the wild. They are well adapted to cope with this sort of issue.

 

[yossaria]

Thanks for the replies. I know that I am new to this hobby and I truly appreciate all the good advice that I am offered.
The tank is 40 gallons with 5 pieces of live rock (lr) in it. I am not terribly certain of the lr weight, but I paid $260 for it and I believe it is $8/pound so I estimate that there is roughly 32 lbs. I have a wet/dry filtersystem which is rated for a much larger tank. I am not sure of the make and model because my tank is in my lab and I am currently at home. There is a 500 gal/hour pump in the sump and a seperate powerhead in the tank to circulate H2O. My specific gravity is 1.023 which is lower than what you recommend for sea stars but higher than what my local aquarium shop suggests. The tank was set up by an agent of the aquarium shop and I maintain it in my lab. I am using the hood that came with my aquarium for lighting. It contains a single fluorescent bulb and I have it on a timer set for ten hours of illumination. I plan to upgrade it when I can afford it because I would really like to keep corals.
The purchased life forms in my aquarium were all suggested by people who work in my local shop. After I bought the live rock, the aquarium was allowed to begin to cycle for two weeks before adding the damsel, cleaner shrimp, sea star, snails and hermit crabs. The next addition came 4 weeks later (yellow pygmy angel, lawnmower blenny, fire shrimp, queen conch, clam, sally lightfoot). The staff at my local shop suggest the addition of two fish because they felt that the damsel may be too aggressive for a single fish. They also said that invertibrates do not contribute significantly to ammonia production so I could add more freely. Please let me know your thoughts on this matter. I take the water to my local store to have it tested and everything has been looking good by their standards. They suggest that I think about supplementing the H2O with calcium in preparation to add corals.
I am begining to see hair algae appear which I understand is a light/nitrate/phosphate issue. I understand that frequent H2O changes can help drive the nitrate and phosphate levels down, but I am unclear about the contribution of light to this issue. Is it possible that too little light can lead to this problem? The main reason I wanted to add more fish to the aquarium was to hopefully combat this algae issue. It had been suggested to me that the blenny, angelfish, sally lightfoot and queen conch would all help eat this stuff which is why they were purchased.
Again thank you for any helpful advice!
Yoss

 

[autofreak44]

All i can say is get a book and take it slow. 2 things i wish i would have done a month and a half ago

 

[ophiura]

Let me give you one piece of advice.
Be wary of the advice of people who are making money from you.
That is harsh, but it is a truth in this hobby.
I disagree with their suggested rate of stocking, and I disagree that things like angels will help with algae problems (or that they should be in such a young tank). The sand sifter star remains a terrible choice for this tank, but most stores sell them anyway. The specific gravity is highly stressful for all invertebrates. Most LFS keep their specific gravity abnormally low. Why? because it helps keep parasites down, specifically, invertebrate parasites. Logically, then, invertebrates that we want to KEEP will also be stressed by lower salinities.
Their comment on damsels make little sense. They are territorial fish - having two fish only means that they will pick on two fish (BTW, they will attack humans in the wild when they dive too close).
Adding fish to combat an algae issue - in particular hair algae - is somewhat defeating the purpose, IMO, as they need more food. With the exception of the lawnmower blenny, none of the others are particularly good at combating hair algae, IMO.

 

[keyah1]

A good lfs will ask about your tank and your water quality and the inhabitants you have. They may even refuse to sell you a critter in fear of shocking your system.