Well, in this case the oyster is the world. At least it is for the many epibionts associated with one of these American Thorny oysters, Spondylus americanus. Thanks to my recent success in acquiring the Spiral corals (and a Rhizotrochus!) my wish list has been looking a bit shorter recently, however it is by no means complete. Another animal that I have always wanted to keep is the Thorny oyster, I have never seen any for sale nor have I been able to source any online. I decided to ask the local shop (the one that found the spiral corals) to look for one for me. Lo and behold one week later they had some. Now I know that oysters are difficult to keep, even a small one may be a stretch too far for my mixed reef tank but I have always wanted to try. I have been able to keep the hitchhiking mussel (Septifer bilocularis?) alive for over 4 years now but it is tiny in comparison and probably also an indiscriminate filter feeder. Still I feed a lot more particulate food and phytoplankton these days so I feel I'm in a better position to give one a go (famous last words!). They had two available, one was smaller and almost certainly the better choice but the bigger one was oh so fabulous, I found it impossible to choose between the two and all form of rational thought flew right out the window. I ended up buying both of them. I have named them 'Syd' Little and 'Eddie' Large (after the British comedy double act). Eddie is covered with so much fascinating life! So far I have discovered 4 addtional bivalves, 2 hoof snails, 2 tunicates, at least 4 species of sponge and a feather worm attached to him! I'm not confident on the IDs but the bivalve on top is possibly a Frond oyster (Dendostrea frons) and the one at the back is possibly a jewel box clam, Chama sp. Of the two remaining bivalves one is an Ark clam and the other is too tiny for me to have any sort of clue what it is other than it being a bivalve. The hoof snails, Hipponix sp.?, were initially intriguing but after doing a bit of research and watching them I came to the conclusion that they were possibly bad for the oyster. I found an article online that stated Hipponix conicus eats the mucus, faeces and mantle tissue of its host plus micro algae growing on the hosts shell. I observed both of mine, on occasion, extend their feeding proboscis right inside the oyster. Perhaps they were simply feeding on mucus and faeces but eating mantle tissue absolutely cannot be tolerated. The oysters don't need that kind of extra pressure to survive, they are hard enough to keep healthy as it is. I don't like killing things but the hoof snails had to go. Apart from the two on Eddie I found another one attached to Syd. The smaller ones popped off relatively easily but the large one took a bit more effort. Each one left a black 'mark' on the oysters shell. To begin with I thought the 'marks' were actually holes in the shell. I feared that the hoof snails had bored right through the shell and by removing them had I made the oysters vulnerable to predation/infection. Fortunately closer investigation showed that the shell was still intact, the snail's foot must have ground away the outer layer of the oysters shell. It's been just over 5 weeks since Eddie and Syd were introduced and the CUC have been checking them out most thoroughly. Unsurprisingly the cowries have been eating some of the sponges, most particularly the pink one on top. I'll be sad to lose it but there's not much I can do about it other than remove the cowries and I quite like having those around too. The Ark clam that was attached bottom right has vanished so must have moved on to pastures new. Both oysters are quite reactive but Syd, the smaller one is really twitchy. He can 'see' me approaching the tank and closes up in response. I don't know if this will harm him in the long run as it must use energy to close/open up all the time, also being closed means less feeding. I will have to wait and see how they both fare. I'll sign off this post with some time-lapse fun of Eddie & friends.
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A fellow reefer was shutting down his tank due to an impending house move and kindly offered to send me some of his cool hitchhikers. I am always looking for any extra diversity so welcomed them with open arms. He sent me two small bivalves, a small rock with an encrusting purple sponge and a handful of mini brittlestars. Unfortunately I made the mistake of adding the brittlestars to same container as the rock for acclimation so when I came to check on them a bit later on they had all managed to pile inside the rock somehow. Therefore I don't have any brittlestar photos to show, duh! I think one of the bivalves is an ark clam, maybe a bearded ark clam, Barbatia sp. (possibly Barbatia candida), the other one looks like a rectangular false cockle, Cardita variegata. I'm no shell expert though so take those IDs with a pinch of salt. After acclimation I placed them on the sand to check for signs of life and sure enough both opened up a little. I'm even worse at identifying sponges so I'm not even going to try to hesitate a guess at that one. The next day the Ark clam had completely vanished, I'd been warned that it liked to go a wandering so I wasn't particularly surprised to find it gone. I tried really hard to find its new location but failed completely. The other bivalve was still sat in the same spot on the sand so I carefully moved that to a spot under the rockwork.
Sponges tend to grow best out of the light so I placed that little rock underneath a ledge. The following day however I discovered one of my money cowries loitering right next to the sponge. I gave it the benefit of the doubt but it became clear later on that the cowrie was actually eating the sponge. The top left part of it had been totally consumed. I immediately pulled the cowrie away but 5 minutes later it was back on the sponge again. Nooo! Clearly this sponge is super tasty or something. I cannot be on hand all the time to defend it from hungry molluscs so I pulled the sponge out and placed it in the sump. A couple of weeks later it seems to be doing OK down there and may even be growing a little so I'm just going to leave it there now. A couple of weeks ago the tank passed its 3rd birthday and I celebrated (not!) by getting the coral cutters out, I had put it off for far too long. I haven't been able to clean the left hand glass for ages and the coralline algae was having a field day. I also took the opportunity to really reduce the over large gorgonian in the middle and trim a few branch tips of the Red Planet. I hate having to cut corals and always manage to accidentally damage other stuff at the same time plus the fish really hate the disruption. After I had finished chopping I found it hard to even look at the tank, to me it looked rather sad even though I knew it really needed doing. The Stylophora looks an odd shape and by reducing the size of the gorgonian I exposed an area of bare rock that I knew would provide a perfect breeding ground for algae. Also there is always a knock on effect when fragging corals, I knew that the alkalinity/calcium uptake would lower (because I'd made that mistake in the past) so I turned down the doser. However I vastly underestimated the difference and the KH level still crept up over the following days. Duh! I think I finally have the dosing level dialled in again after days of testing and retesting. I also took the opportunity to add a few more money cowries to keep the growth of algae on the rocks under control. The Stylophora has recovered well, the photo below shows a couple of the branches 7 days post fragging. After 9 days the cut tips were fully covered and the tips had developed polyps after 14 days. Kandinsky the Mandarin is doing well and is fat as a sausage. He hasn't managed to eat all the copepods in the tank...yet! When the glass has not been cleaned for a few days I can still see them scampering around (during the day too) which makes me very happy. Admittedly they are located more towards the top of the tank where Kandinsky does not venture much but if they get a chance to reproduce and spread elsewhere that's got to be a good thing. Spike has proved to be a bit more frustrating in the feeding department. He loves lobster eggs and live copepods but isn't much interested in anything else. I hope that this will change in the future. Firefish have a reputation of being shy and hiding but not this fish, he's out in the open all day long. A few coral shots. Lastly the requisite FTS. I must have taken in excess of 300 photos in an effort to get all the fish in view at the same time, this was the best of the bunch. There is still one fish not on show but I'll save that update for the next blog posting.
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AuthorHi, my name is Lisa and I live in Derby, UK. I am a self-confessed reefaholic! Archives
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