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Oyster Reef Ecosystem Tank


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Last night, I removed the remaining complete oyster and clam shells, and the PVC pipe. I'll glue the compete shells and place them strategically into the tank tonight to provide additional hiding spots. Once I build the larger reef, I'll wind up gluing these to the other sections of the reef that are currently not in a tank. I placed the improved structure with the repaired overhangs in the tank, and I'm really happy with how it turned out.

I moved the remaining shells in the tank that were halves or pieces to the front of the tank until I decide what to do with them. I will keep the ones in there that have good "life" on them. I may or may not keep the others. What I've learned is that eventually, some of the shells, even complete oyster shells, will be buried in the sand. Current and critters cause this. I have no idea what happened to the mud crabs in the tank. They may still be in there, but I haven't seen them. They could have been in the reef when I removed it for repair, but, I never saw any sign of them climbing out. I might find one on the floor in the rec room some day, LOL.

Anyway, below is a pic of the remaining shells that I glued lat night. I use a clothes pin to create a 1/2" gap. There was a journal written about the gap preferences of striped blennies (and other benthic fish) for breeding purposes, and their findings showed that 1/2" was the optimal gap. I glued the inside base of the shell with Gorilla Glue, placed the pin in the front of the shell, and used rubber bands to bind them until the glue dried. The clams need less glue, because the joint is stronger than oysters. I used the clothes pin for them too. The clingfish prefer the clams, it seems, but that may be because the blennies prefer and use up the oyster shells. In truth, when hiding, they all use anything available. Here are my gluing efforts, and results:

The tank was too cloudy last night because of the work that I did removing everything, so I couldn't take a pic. I cleaned out the filter and put in a new pad. Hopefully, the filter will keep working. Last night I found it had stopped. I cleaned it out again and the impeller was stuck, so I freed it. Although it's noisy, it was working after the repair and cleaning.

I took a pic this morning after the filter did some work. I don't have an FTS before the repairs (with the overhangs collapsed), but here's a video where you can see it in the first 30 sections. After that, the pic shows it all repaired:



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I "planted" the remaining complete oyster and clam shells throughout the tank, some placed on the reef structure, some in the substrate. I grouped most of the razor clams together to simulate a colony of those, and moved the half oyster shells around the bases of the reef structure. I think that it turned out pretty well, very similar to the early days of the reef. I may move the two major cultches on the right side a little tighter together, and more to the left, to create additional open space under the overhangs. Overall, I'm happy.

The fish seem happier, much more bold today than the past few days, coming out for food and even eating out of my hand. The one skilletfish that I'm worried about is still not eating...I'm not sure at this point that there is anything I can do for it. It doesn't look all that bad, so maybe it will turn around, we will see. If it starts eating again, then I'll feel much better.

Here's the latest FTS:


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I shot a couple videos and uploaded one to YT last night. The fish are still skittish from my hands being in the tank so much. To them, it must have seemed like Godzilla crashing through town when I broke the scape down and set up up again. The fish are cruising the structures and checking out all of the new hidey holes, re-establishing territory, etc. My guess is that egg laying will start again pretty soon. The males are all nicely colored now, which is either a good sign that they're going to spawn soon or that their happy in their new oysterscape. It could be a little of both. Anyway, hope you like the video:


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Bad news:
My largest male blenny committed suicide, and jumped out of the tank last Thursday night. I found him all dried up on the floor. I had one small spot that they could get out next to my HOB filter, and that's where he was, on the floor, under that spot. I found a temporary solution to fix that issue. I don't know if it jumped because of me rearranging the tank and huge water change, or if it was spawning stress from rival males. The tank is almost like it was before, with even more hiding spots. I thought that they might resume finding the same shells that they had before, but, they seem to have found new spots to defend.

Good news:
I think that I mentioned that during the winter, with water temps dropping into the 50's, that my fish pretty much stopped laying eggs. The amount of daylight might have something to do with this cycle too, as there is exposure to daylight via a nearby window. I didn't see any other spawning activity during that time. I was a bit worried about that.

However, things are beginning to happen again with the blennies. Now that spring in my area has arrived, and tank temps are now around 62F, they've started some spawning activity, but the male blennies are all fired up. Also, when I broke down the tank, I found a shell with eggs in it, so, it's not because of the giant water change. Things were already happening and I just didn't observe it.

In this video, you'll see a male striped blenny (Chasmodes bosquianus) flash and chase a female, trying to lure her to his shell. He is interrupted by a rival male, and a confrontation ensues, with the first male winding up chasing the other one off. Enjoy!



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Last week, I showed males starting to get aggressive due to spawning activity, re-establishing their territories, more actively defending oyster shells, sparring with each other, and flashing the female while trying to herd her towards their shells.

This weekend, for the first time since I broke down the tank, I found a male guarding eggs. I wouldn't be surprised if the others are also guarding eggs. I can't tell because they both hang out behind the oyster structures out of sight until I feed them.

I was worried about this particular male before I broke the tank down, because he was the smallest male. He was picked on and chased by the other males, and was the only one that hadn't bred with the female, to my knowledge. Now, he chases away the larger males and defends his shell as brave as any blenny possibly could! And, his shell is right in front of the tank for me to film. Soon, there will be fry swimming around again. Here's a video showing the eggs and other activity around the tank, and also, later in the vid, you can see the female skilletfish stuck to the glass, and can easily see that she's ready to lay eggs too. Hope you enjoy the video, thanks for watching.

I guess my theory was correct, that when temps in my basement went down, breeding activity came to a halt. When they crept back up, it resumed. I suspected that would happen before the winter began. There were eggs in a shell when I broke the tank down, and they've resumed again a few weeks later.


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I was thinking about the health of my tank last night. My fish seem to thrive even though it's a small tank. I have 11 fish that are between 3 and 5" long. They're all fat and breeding. When I caught all my fish, they averaged and inch long, and grew to adult size in about 8 months. I've had this tank set up for two years now. I began with 7 striped blennies, 5 skilletfish, and 5 naked gobies. I now have 4 striped blennies, 2 skilletfish, and 4 naked gobies.

How I lost fish:
Blennies - One adult female blenny jumped out of the tank after my disease outbreak while being treated in QT. The other blenny lost was a male that jumped out of my DT a couple weeks ago. I had one adult male blenny die after going blind about 6 months ago.

Skilletfish - Two adults died of disease during the outbreak, one just went missing this week (it was the one that wasn't eating). I assume it was an internal parasite.

Naked gobies - I lost one a few months ago, unknown, found dead but seemed healthy until then.

I haven't been testing my parameters in months. I got lazy, so last night, I tested for ammonia (zero), nitrite (zero), nitrate (50). I thought that if a fish was missing and died, that the levels would have been elevated, but not, so I was surprised by that.

Invertebrates in both tanks:
Ghost anemones - I had three in my DT and thrived until I returned my fish from QT, then they disappeared. I had three in my invert tank, and one is huge and thriving. The others could be alive somewhere in the oyster cultch. They move around a lot and are hard to see, but I haven't seen them in a month or so.

Tunicates - I had them in both tanks. They live about 6 months as adults then die off. Every now and then, I'll find one inside an oyster shell, but haven't seen any in a while now (about three months). There could be some deep in the cultches, but I may have killed them when I pulled the reef apart for repair, because the reef was dry for a few days.

Barnacles - Some died that I collected, but, I still have a few (2 different species) that have lived for over a year now and are doing well. I think that once they survive the early stages of captivity, some adapt and do well if fed properly.

Mussels - Same as barnacles, I've collected and kept about a dozen of them between the two tanks, but most have died off. I still have four alive that seem to be doing well that are a year old now.

Grass Shrimp - I've been able to keep them in the DT with the fish for about 6 months, then they gradually disappear. Some jump out of the tank, and I think the fish killed and ate some too. In my invert tank, they can't get out, and have lived over a year now. I started with about 30, and there are about 20 left, but, they're hard to count because they move around a lot, and hide throughout the reef. So, there could still be 30 in there.

Mud Crabs - I've kept two different species. In my DT, I didn't find any when I pulled out the reef, but, there could still be some in the tank. They hide in the reef and also bury themselves, and I really didn't look for them. Some may have died or crawled away when I pulled the reef out of the tank. I haven't found any on the floor though. In my invert tank, there are 6 mud crabs, at least, that I see now and then.

Bristle worms - They are doing well in both tanks. I see them out all the time in my invert tank, but never come out in the fish tank. I see them burrowing around the glass in the sand though, so they're there. I think that they only come out at night.

Amphipods - The fish ate all of them in the DT, but some are still alive in my invert tank. I see them now and then feeding on algae on the glass. They're nocturnal, and very wary, and hide all the time.

Copepods - I had a bunch that I always saw on the glass, but since I used Prazipro, I haven't seen any lately. It might be because I cleaned the glass, but I used to see a few even then. The glass is starting to get algae again, and is due a cleaning, but I think I'll wait and see if any pods appear. I never see any in the invert tank, because I think that the anemones eat them. I'm sure that some are living in there though.

Snails - I found one lone micro sized snail living in my DT when my fish were in QT. But, I haven't seen it since the fish were returned. The fish may have eaten it.

One possible thing that could have happened is that maybe some of the inverts that died off in my DT when I returned my fish from QT, could have been due to elevated ammonia. I did water changes during that time and tested, and there was some ammonia and nitrite present, prior to the water changes. That could have caused the die off rather than the fish eating them. I don't think it would have affected the grass shrimp, but the anemones and snail could have been victims due to that.

So, the question, in my mind, is, will some of these inverts survive with adult fish or are the fish killing them? Ultimately, I'd like to keep the whole cast of characters, a true biotope. We will see.
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