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Oyster Reef Ecosystem Tank


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I've posted a bunch of videos of late, and realized that I don't have that many recent pictures.
A lot has changed in the last 6 months. The fish are all full size adults now, and all three species are breeding. They have their favorite shells that they hang out in, and don't stray far from them, especially the male blennies. When these fish are guarding eggs, most of the time, only their heads peek out of their oyster shells. They venture out and check out their perimeter of about a radius of 4", now and then, and further only at feeding time. They will eat, then bolt back to their shell. The female blenny is the lone exception, as she roams the tank and breeds with all of the males.

Much of the tank range of these fish are determined by these established territories, and these territories seem to be based on a pecking order, with the blennies claiming the best spots and defending them rigorously, especially against each other. However, since they don't stray far from their shell, confrontations are few.

The three species, for the most part, tolerate each other except when a fish moves too close to their favorite shell, and is chased off. The pecking order appears to be that the blennies are the most dominant, but pretty equal against each other, followed by the skilletfish but not far behind. Male skilletfish tend to defend their shells rigorously as well. The gobies are probably the least aggressive, but very brave, as they will put up a good defensive front against the other species and try to chase them away. They tend to back down and flee if challenged in return, though.

The females of each species are the most mobile and hold more vague territories, not necessarily restricted to a single shell. Here are some recent pics:

Female striped blenny (Chasmodes bosquianus)

Male striped blenny:

Male striped blenny, guarding eggs:

Skilletfish (Gobiesox strumosus):

Female naked goby (Gobiosoma bosc), the males look the same but are a bit larger:


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Here's an interesting video I shot the other day. I went to feed my invert 20g high tank, and noticed this freaky worm swimming fast around my tank. At first, I thought it might e a new species, but after doing some research on the net, it's probably one of the clamworms sporting a swimming reproductive phase. I read that they're mouthparts are useless at this stage, as is their digestive tract, and that they'll die after they've spawned. I think that is the case. If someone knows more, please post about it.



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Look what I found in my tank last night! I spend time each day watching this tank, and let me tell you that I thought that I knew what was going on at every inch of visible space in the tank. But, last night, right in front, I found a new plant sprouting up, and I think it is widgeon grass. For those that have followed my thread, you may remember that I've introduced this grass in my tank many times, and each time it has died off. The key to getting it to grow is to make sure it roots, and although, I tried to do that, it never worked. Well, now this sprout appears on it's own, and I couldn't be happier. It may be too early to ID it, because it could be another form of algae, but it sure looks like widgeon grass to me. So, I guess this makes my tank a sea grass tank now!!! If this stuff tanks off, maybe it can out-compete the other less desirable forms of algae and slime. Anyway, here's a pic of it, followed by a video of it and a general pan of the fish to show you how their doing.

Here's the vid:


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Here's a vid from last week, not the best quality, but all of the critters poked their heads out to say hi:


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My fished posed again for me, so time to share some pics again.

Male Striped Blenny (Chasmodes bosquianus):

A pair of male striped blennies challenging each other's territory:

A skilletfish (Gobisox strumosus), blending in:

Side view of a skilletfish:

Another angle of a skilletfish, and a female naked goby (Gobiosoma bosc) inside an oyster shell:

Another male striped blenny peeking out from a crevice:

The queen of the tank, a female striped blenny:

A handsome male naked goby.


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There isn't much different going on in the tank than my last update, but, even when I don't have time to watch it, I wind up watching for an hour or more. So, this is part of my hour watching last night, right before feeding time. I snuck in before they could see me and beg at the glass for food, almost. One skilletfish was waiting for me before I got there. I feed them at about the same time every night. I wonder if they also have "internal clocks" like we do. Hope you all like the video:



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Not a good report today...I lost one of my skilletfish. I can't find any visual cause of death. The fish was eating well, good weight, seemed healthy just the night before, with no signs of parasitism, and I found it dead, belly up on the bottom last night. I checked ammonia and nitrite and they were zero, so not sure what happened. All of my fish seem healthy, no scratching. The only thing that I could think of is that it could have been an internal parasite, but I'd expect it to look sickly. Weird.

Well, these fish are two years old now, so maybe that is their life span? I need to research this.


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I also keep a 20g high oyster reef brackish aquarium, but this is an invertebrate tank only right now. I don't know if I'll keep fish in it or not. I don't do a ton of maintentance on it, just let the inverts do their thing, feed them daily with flakes, and feed the anemones and crabs frozen shrimp now and then. There are at least two species of mud crabs, 3 ghost anemones, about 20 grass shrimp, a few live mussels, a few barnacles, a bunch of amphipods that rarely come out, and a bunch of clam worms (bristle worms). I feed the filter feeders oyster egg solution as well a couple times each week. Once in a while, I get a treat when the crabs, amphipods come out, and also like to watch the anemones eat. Well, last night, I had quite a surprise when I found a grass shrimp feasting on live remains of a half eaten bristle worm that was in the swimming/mating form. I never thought that grass shrimp would do that since they're so timid. I always thought bristle worms would be aggressive too, but, they are not at all aggressive and really help as part of the clean up crew. Anyway, I have a short video of the grass shrimp feast:


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Last week, I noticed another skilletfish acting weird, not coming to the front to eat, breathing heavy, not interested in food if I put some near it, etc. My fear was that it was going to die like the other one did, mysteriously. So, I decided to treat it with Prazipro, thinking that perhaps I never got rid of the flukes. My reasoning was that a couple gobies have been scratching for a while now, not going crazy or acting sick, but, that is a sign that it could be flukes. Anyway, that was Wednesday night.

On Friday night, I got home, took out some leftovers for dinner, put them in the microwave so that my wife and I could eat dinner and watch a TV show. While the food was in the microwave, I went downstairs to check on my fish.
The sickly skilletfish was still in the same shell, doing the same thing. The previous night, at feeding time, only two fish came out to eat, the others hid in their shells, although a few of them did eat when food drifted by. But, normally, they all come out to eat out of my hand. I shined my flashlight around the tank, as not many fish were poking their heads out, and that worried me. Inside one of the shells, I noticed one of the male blennies upside down, breathing heavy. There was another male blenny that wouldn't come out of his shell and eat that I noticed the night before too, and he had me worried.

I went into panic mode. I had plenty of circulation and aeration in the tank, but, maybe the fish couldn't take the meds. So, in my mind, 90% water change, so I drained the tank. Only a small amount of water was in the tank, with the fish.

While I was at it, I figured that I'd pull out the oyster cultches and fix some of the things that fell apart over time. For example, there was an overhang that I thought was really cool that broke apart and fell, and I really wanted to fix it. There was another couple of oysters that fell off that weren't originally glued well also. These things really bugged me, even though things looked OK in the video, I hated knowing that it wasn't as I had planned.

Of course, pulling out the reef meant that fish could be in the reef, out of the water, and I had to shake a few fish out. The blenny that hid in his shell wouldn't come out that I was worried about was one of the fish that I had to shake out. I finally did, and then I saw why he was behaving that way...not disease...he was guarding eggs! Well, that was good news.

Anyway, I thought the upside down blenny was dying for sure, but, after removing the reef, I counted all of the blennies swimming around just fine. He was probably just in the shell, as they always do, acting goofy in his shell. I panicked for no reason.

Of course, when pulling the reef out, I was worried about leaving a fish stuck in it, but as it turned out, all of the fish were accounted for. I didn't find any crabs, so I don't know what happened to all of the crabs in the tank. They could still be in the tank buried in the sand. I hope that they weren't in the reef, because it's been out of the water under repair since Friday night.

I filled the tank with newly mixed brackish water, increasing the salinity just a tiny bit. I left about a dozen loose oyster shells in the tank for hiding spots, and tossed in a half dozen PVC pipe sections for additional hiding spots, with the hopes of calming the fish down and easing potential aggression.

Anyway, I repaired the large overhang and it looks really good:

I beefed up the two other overhangs and any other loose oyster shells:

I also removed a dozen complete oyster shells that I collected that were laying by themselves on the sand, that were loose or had come completely apart, with the purpose of gluing them together. I also wanted to glue them to the cultches to provide more hiding spots on the main structure. The clothes pins are about a half inch thick, and are perfect spacers for gluing open oyster shell hiding spots. I used thick rubber bands to since them tight so the glue would hold nicely.

After they dried, last night, I glued them onto each of the structures pictured above, adding a dozen new open oyster shell hiding spots solidly to the structure, Previously, these shells were either lying on the bottom of the tank, or loosely stuck in crevices in the reef.

The problem is that, even though the dead oyster shells are great cover, and the fish use them, they eventually come apart and become litter on the bottom of the tank. I wanted something more permanent. And, since they also like the permanently glues ones on the reef, I figured more is better.

Tonight, I will remove the remaining oyster and clam shells from the tank and repair them. Then, I'll place the oyster reef back into the tank, and tomorrow night, place the repaired oyster and clam shells strategically in the tank (where I can easily observe them). I need 24 hours for the glue to cure.

By the way, I used Gorilla Glue again. Most of the reef is still really solid, so I'm happy with how it held together over time. I just used more of it on the overhang, and it's really solid now. I just didn't use enough glue the first time. Also, last night, after gluing the new hiding spots permanently on the structure, it looks really good. I couldn't be happier.

I still am not sure what to do about the "sick" skilletfish. I may QT it and try and treat it. Maybe the water changes will help it recover, I don't know. I'll do another one tonight, maybe 50%. The rest of the fish are doing OK, although disoriented because their favorite hiding spots were removed. I think that once I return the reef to them, they'll get back to doing what they do.