Oyster Reef Ecosystem Tank

[Chasmodes]

Hi everyone! I just found this site today and it seems like a really cool place to share info. Not only am I building my dream tank using locally collected species, but I'm trying to duplicate as close as possible an oyster reef biotope.

Concept:
One of my dreams was to duplicate the oyster reef environment of the Chesapeake Bay as best I can without much predation. The feature fish will be the striped blenny, Chasmodes bosquianus. All other organisms that I collect and keep will be fun, but the focus is on the blennies. So, at first, this will be like a fish only tank with macroalgae, but eventually I'd like to turn this into an entire Chesapeake Bay oyster reef as much as possible. I will not keep blue crabs, toadfish, any other predatory fish, or mantis shrimp. If it doesn't eat blennies, I may keep it.


I had a tank and sump built for this a several years back, and almost finished a stand but personal troubles in my life caused me some delay in the build. The tank is an acrylic 101 gallon cube (36"X36"X18"), and the sump/refugium is 36"X18"17". I hope to gather "live" sand from the Chesapeake Bay, and I'm going to try a Chesapeake Bay mud for the refugium. I will introduce macroalgae early in the process in the sump and perhaps the display tank as well. I want to have plenty of life in this tank prior to adding the fish.


Once the tank is established, I hope to obtain additional filtration using live filter feeding organisms, oysters and perhaps mussels, tunicates, sponges, etc. although I realize that I'd have to find some way to supplement feeding. The sump will hopefully be a good supply of planktonic critters, although I may try to build a plankton reactor later on if that doesn't work.

My stocking list will include, but not be limited to:

1. Striped blennies (Chasmodes bosquianus) - will be the feature fish of this tank. I hope to get them to breed, so there will be at least half a dozen of these.
2. Hysoblennius hentzi - feather blenny if I'm lucky enough to catch any. They're aggressive, so I am undecided on them. I had one a long time ago, and it was an awesome fish.
3. Naked goby (Gobiosoma bosc)
4. Skilletfish (Gobiesox strumosus)
5. Northern pipefish (Syngnathus fuscus) maybe, once my tank is estabished.
6. Other possible fish that I may add include seahorses, a hogchoker, killifish, mummichogs, sheepshead minnows, and if I'm really lucky, maybe a tropical stray spotfin butterflyfish.
7. Ghost shrimp, hermit crabs, snails, etc. for clean up crew that live in the bay.
8. And just about any critter that comes in on the rocks eventually. I'll run the tank fallow for 6 weeks after the tank cycles to reduce parasitism before adding fish. I will QT fish prior to adding them to the tank.

Biological Filtration:
I'll attempt another reefkeeping technique, live rock. However, the rock in my area of the bay typically is composed of clay and is of no biological use. I've built some DIY rock out of cement, and will place themin the bay at my friends place. After a while, once they're full of life, I'll place them in my sump. This rock, plus the live sand as my substrate should adequately address the biological filtration needs of this tank quickly.


Ecological Simulation:
The Chesapeake bay is brackish and the salinity varies based on rainfall and runoff, but these fish have bred in captivity with a specific gravity of 1.015 or so. The range where I will collect varies between 1.015-1.020 depending on rainfall, time of year, etc. I'll keep my tank in this range, probably more on the salty side for now. Eventually, I may bring it to full salt, although varying salinity might help control parasitism. I read one article that you can vary the specific gravity as much as 0.002 per day. I don't plan on doing it that much, but, I think that I don't have to worry about the fish being sensitive do changes of this over time.


Temperatures range from winter cold water in the 40's F to brutally warm summer temps in the upper 80's F in the shallows of the bay. Chasmodes bosquianus and the other fish are also found in Florida waters, so I don't think that temperature is an issue and won't need a heater or chiller. Water parameters in the Chesapeake are constantly changing too, making it tough for sensitive species to thrive there, but these changes are no problem for species represented in this biotope. I will keep my mind open to the possibility of using a chiller if I can't get the blennies to spawn, but I don't think it will be necessary. We will see.

Lighting:
I'm looking at using freshwater LED lighting that is suitable for a planted tank. It's not wattage and intensity that I'm after, but rather I want to duplicate lunar cycles, daylight and nighttime lighting transitions and seasonal variances in an attempt to induce spawning behavior.

Water Quality:
I plan to not use a skimmer and hope to cultivate macro algae for nutrient export. Eventually, I'll try keeping filter feeding organisms, especially in the sump, once the tank is established. I think that most of the invertebrates will be hydroids, hardy anemones, tunicates, oysters, barnacles and mussels, and other filter feeders. Eventually I may use supplemental planktonic feed products perhaps. These inverts don't need as much light. Bay waters are pretty murky and filled with nutrients (both natural and, unfortunately, man introduced). Of course, frequent testing and water changes will be in my regimen to make sure that things go well. My main concern isn't so much the inverts here, but getting my fish to breed and thrive. If the biotope works out and I can keep all of these critters successfully, then so much the better. Top off water will come via using an RO/DI unit.

Current:
Another thing that I'd like to simulate is the tide and water movements. I don't want to do this by lowering and raising water levels, but rather by using varying currents. I can use directional flow to simulate water moving in and out of the mouth of a tidal creek for example, where a dock with an oyster reef may reside and form the habitat that I'm trying to duplicate. I think that I can do this by having powerheads on timers. Not only will this help keep the critters feeling at home, frequent current and no dead zones in the tank should help with algae control.

In addition to placing DIY rock in the bay, I think that I can also make a basket/milk crate and fill it with oyster shells to collect animals. I have permission to a couple good collecting spots to place these. The oyster shell basket will allow me to easily collect various oyster reef fish. I may also get more species diversity this way, including invertebrates. Dip nets work well, especially for tough to catch fish that won't hide in the oyster shells.


Other issues:
One issue surrounds the collection of live oysters. In Maryland, I have to be careful that if I collect my own, to collect in designated areas and during the correct open season. Even though they aren't for consumption, I need to make sure that I'm compliant with local laws which change frequently. A better option would be to buy some fresh oysters directly from a waterman, right off the boat. It will cost me some money, but at least I'd know that I'm legal, and it's good for the local economy.

I think that in this system there may not be a wrong way to do it simply because these animals are so hardy. That said, I'd like to create a successful system and give these animals optimal conditions. This system won't have the color and beauty seen in the typical reef aquarium, but it will have it's own appeal and beauty, and quite unique from other tanks. Actually, the male striped blenny gets extremely colorful during spawning! If that happens then I'll know I'm on the right track.


The creation of the ecosystem is a goal, but having an accurate and complete one might be out of the question. The blennies are the feature fish, so those will be my main concern, and that is creating a good breeding habitat with the simulation of an accurate biotope. So, my goal of keeping filter feeding invertebrates might not be doable. I'm going to give it a try though.

I have no idea what problems I will encounter. Algae blooms are a primary concern. I hope that macroalgae will outcompete the nuiscance algae. Another concern is parasitism. Between running the tank fallow prior to adding fish, and having a QT system already in place, parasitism should be kept to a minimum.


As far as the aquascaping (or rockscaping) goes, I've made progress. I collected oyster shells from restaurants (even bought and shucked some of my own), matched as many as I could, glued them together into what I think are realistic looking oyster cultches to build the reef. I used Gorilla Glue to glue them all together into a reef. It was a long and tedious process, but I am satisfied with the result. I posted a picture of the final product below. Included in the reef are several dozen oyster shells that are glued in an open position, some with larger gaps, some smaller. The gaps are the exact size of gaps that the blennies (larger gaps almost 1/2" wide) and gobies (smaller gaps about 3/8" wide) prefer for breeding.

 

[Chasmodes]

Here are some pics of my build so far:

Tank

Sump

Stand (build in progress)
Need to build a face frame, add cabinet doors, and some finishing touches.

Aquascaping
This is the environment that I'm modeling the aquascaping after, except that in the tank it will always be submerged:

My Oyster Reef - almost finished, some minor things to add, but basically, this is the reef. My unfinished tank stand makes for a nice workbench . The stand gives you the basic dimensions of the tank, along with the measuring tape behind the reef on the right side:

Here's a video:

Next steps:

1. Finish the stand.
2. Purchase pumps, lights, new RO/DI unit and other equipment
3. Set up water changing station, sump, and complete plumbing to the tank.
4. Leak test tanks
5. Collect sand
6. Fill tank, cycle, and run fallow for about 6 weeks
7. Set up quarantine tank
8. Begin collecting livestock

I have a lot to do! Thanks for looking!

 

[Sploke]

Very cool concept, looking forward to watching the progress!

 

[ProjectMaro]

watching

 

[Chasmodes]

A lot has happened since my last post. My 100g tank still is not up and running. But, I've set up two tanks, a 20g long and a 20g high that are stocked with fish. I want to have my 100g up and running this winter fully stocked. So, to do that, I set these tanks up this summer with sand and added my oyster cultches (like mini oyster reefs), went out and collected fish, inverts and macros and stocked both tanks. The idea was to transfer everything to the new tank incrementally to speed up that cycling process once it is ready. In the meantime, I get to enjoy observing my fish and other Bay life in the tank.

First, the 20g long. This tank is more of a display tank and is visually appealing. However, as the tank ages, I'm going through bouts of cyanobacteria blooms. This tank is heavily stocked and fed, so the nutrients are there to support macroalgae. Either the macros are being out competed by the cyano blooms, or the lighting is insufficient. Nutrient export is achieved by removing cyano manually and via weekly water changes (or more often if needed). Green hair algae was present for a while, but has pretty much died off (some remains, but not much). Cyano occurs in the red and green form. I do a 30% change each week. The fish are doing great as are the inverts.

I cycled the tank, then added fish and macroalgae. Some invertebrates hitchhiked into the tank as well. This tank has a HOB filter and a powerhead, with about an inch deep sand bed (just play sand from the hardware store), and I added the smaller of my oyster cultches as structure for the fish, visual appeal, and also as a base for beneficial bacteria to thrive (like my version of live rock). I have a basic FW light fixture.

I don't think the lighting is sufficient to grow macros in this tank. I added some red algae (Gracilaria sp. I think), green algae (Ulva) and and although it looked great, it isn't thriving. Also, I tried adding widgeon grass. I didn't think it would live though because it's such a new tank. I think the nutrients aren't an issue for it, but from what I've heard, it needs the right substrate and nutrient base in the sand bed to thrive. It didn't root and died, so I tossed it. I'll save that experiment for the larger tank.

Livestock:
- 6 juvenile striped blennies (Chasmodes bosquianus) ranging in size when I got them from 1" to 2". They've all grown about a half inch over the summer.
- 5 juvenile naked gobies (Gobiosoma bosc) that were about an inch long when I introduced them to the tank, but have all grown about 1/2 to 1" since then.
- 5 juvenile skilletfish (Gobiesox strumosus) that average about 1 1/2" long right now. They've grown some, but not at the rate of the other fish.
- 2 juvenile mummichogs (Fundulus heteroclitus) that are about an inch to 1.25" long. I wanted a species of fish to fill out the upper part of the water column rather than have all benthic species.
- 3 Harris mud crabs (Rhithropanopeus harrisii) that are about 1/2" - 3/4" across (shell width). Hitchhiker.
- 1 brown black-fingered mud crab (Panopeus herbstii) about 1/2" across. Hitchhiker
- grass shrimp, not sure of exact species. I had about a dozen initially. A few were eaten and some jumped out of the tank, but there are about 8-10 left in the tank.
- Other hitchhikers include 2 bryozoan colonies growing in the glass in the darker areas of the tank, and an unidentified non-parasitic isopod. There is also evidence of worms based on worm trails in the sand bed.

The fish are all healthy and active. I feed them flakes in the morning via an autofeeder, and frozen brine shrimp each evening.

Here's a FTS of the 20g long:

The 20g high was initially a holding tank, but is now sort of a display tank. I placed oyster shells and a large cultch in the tank for visual appeal, fish structure, and to house beneficial bacteria. I have two clamp on shop lights with standard LED bulbs as lighting, a HOB filter and a sponge filter. I have both species of macros mentioned in the other tank growing well here, so lighting is sufficient as are nutrients. I haven't had to prune macros yet, but, they seem to be not dying off and growing somewhat.

Livestock:
- 6 adult striped blennies (Chasmodes bosquianus), at least 4 are males for sure. The males have a bright blue spot on the dorsal fin. Two of the blennies lack the spot, so I think that they're females. The sizes range from 2.5-3.5" long.
- 5 adult naked gobies (Gobiosoma bosc) that range in size from 2-2.5".
- 3 adult skilletfish (Gobiesox strumosus) that are about 2.5" long.

Ulva and Gracilaria macroalgae are doing well in this tank. There are some cyano spots and a couple oyster shells with good amounts of turf algae. I will try and collect some cerith snails to help control the algae growth. The fish are fat and healthy. I feed these fish flakes in the morning, and chopped clams, mysis shrimp, and flakes every evening. They are pigs.

Here's a video of this tank, following the largest blenny around:

Here's a full tank shot:

Here's a video of the fish after feeding:

And a video of the 20g high at feeding time:

There are more videos of both tanks and fish on my YT site. I'll post new ones in this thread later as time goes on. Ultimately, all of this life will be in the 100g, hopfully, this winter.

Thanks for watching!

 

[Chasmodes]

More observations: I learn something about their behavior each day. I had some doubts about keeping this many benthic species in a limited environment (even 100 gallons). But, what I've learned are the following:

- If the fish can handle the nutrient load of feeding them, then they seem to "get along" just fine. They do chase each other, even a little fin nipping. But, the picked on seem to heal up fast, and sometimes fight back. After they get chased, they don't hide in a corner of the tank or behind a filter, they go about as if nothing happened. This is true for all of the species in the tank.

- After my last collecting trip, all of the blennies and gobies came from one oyster box that is smaller than my 20 gallon tank. I'd say that they can get along just fine in a small tank environment based on that alone. I read so many posts about people worried about multiple blennies in a tank. I suspect that it depends on each species, but these are pretty aggressive carnivorous blennies, and with enough specimens to "spread the love", nobody gets picked on more than the others.

- Lots of hiding spots is the key, including good escape routes. These escape routes can be crevices in rock (in my case, between oysters in the cultch), through a mat of macroalgae, or within a hiding spot.

- Sometimes when a blenny gets chased, it simply spins does a lap around an oyster shell enough times that the fish doing the chasing either gives up or loses interest.

- Skilletfish are fearless. But, I'd say that all of them are not really afraid of each other.

- I was worried about mud crabs being a threat to the fish. After watching them around the fish, I no longer fear that as an issue. Blennies, gobies and skilletfish often land on them with no reaction from the crab, except sometimes they shoo the fish away with a claw, but do not try to pinch the fish.

- Grass shrimp live much longer in these tanks than I ever imagined. I thought that they'd be all eaten within a week. I'm pleased about that.

 

[Chasmodes]

Correction: In post #5, the first video is of the 20g long.

Also, in the 20g high, other livestock include the same species of shrimp and crabs that were introduced to the tank as hitchhikers, along with bloodworms and sandworms that I never see except when I rearranged oyster shells one time. The shrimp numbers were in the twenties, but now are down to about a dozen or so. It's tough to count them, too many hiding spots, tough to see them, etc. Some probably have been eaten, and a couple jumped out of the tank. Both tanks have full covers on them. I also introduced two killifish that I thought were mummichogs when I collected them, but now think that they might be banded killies. You can see them in the first 20g high video. They appear to do some spawning dances of some sort a few times in the video. They do this often. The only reason that I think that they might not be mummichogs is that the coloration doesn't seem right. Anyone know for sure what species they are?

Some other facts. These tanks are kept at room temperature in my downstairs level. Water temperatures are now at 75F degrees. I expect these to drop to the mid 60's over the winter. The specific gravity remains at the same level as where I collected the critters and plants from at 1.016. Eventually, I may increase it to about 1.020, but am happy with it for now.

 

[Chasmodes]

Quick update:

Both tanks seem to have an increase in itching/scratching behavior. I don't see any visible parasites, but that doesn't mean they aren't there. It's hard to get a good look at them anyway because they move around so much. In fact, I'd say that there likely have been parasites in these tanks all along. All of the fish have scratched a little since the beginning. It's just more frequent now. So, what to do.

My assumption is that the culprit is Cryptocaryon irritans simply because freshwater ich doesn't seem to tolerate any salinity. From what I've read, C. irritans doesn't care for freshwater, so my initial plan is to reduce the salinity and perform a long term hyposalinity treatment.

Currently, the sg is 1.016. I plan to reduce it to about 1.009 and keep it that way for several weeks for each tank. I'd like to have these fish healthy by the time I get the big tank set up.

These fish are very hardy, so I don't anticipate any problems. The shrimp should be OK, as they are commonly caught at a lesser salinity than what I'm doing. My guess is that the mud crabs will be OK too, but I'm not 100% sure. I doubt the Ulva will make it through the process, but we will see.

 

[SnakeIce]

That seems to be par for the course for wild collected fish. You will have gotten off easy if that is all they brought along. I like the concept and the fish seem to be quite interesting in behavior.

 

[Chasmodes]

You may be right, Snake. The hypo treatment should work on most of those evil pests. I don't see any signs of bacterial infection, so that's good. I guess the only other culprits that I need to worry about (or not worry about) would be internal parasites.