Balancing refugium

[sagedrake690]

Heya guys! I apologize beforehand for my long post but there is a lot of information and weird thing that happened. I am somewhat new to the hobby. I have read basically everything you can about everything concerning the care of horseshoe crabs and their husbandry as well as everything I can about keeping aquatic life alive (the goal is to balance it so perfectly you never have to open the lid). I am currently talking to Anthony from kepley biosystems (horseshoe crab biological harvesting and propagation facility) My main care focus is on these three cute little arachnids but I want advice from professionals about my setup. I am looking to breed them to repopulate so I can say I'm helping the planet! Also I want them to be happy not like in a lab lol. I have them in a 5 inch deep acrylic tub as recommended by every online source as these creatures are NOT reef compatible. They like brackish water and troll around in the bay in sand flats as juveniles and hang out near the shelf as adults or around the shallows. They are destructive when they dig and they like to push rocks. I have been observing them for over 2 weeks now and noticed they like to push the small rock around that I have in there. I have no idea what this is for but they do it frequently. My assumption is entertainment. They are also messy. They sift and which would require sinking food that has been softened or crushed fine and this leads to big nasty tanks fast.

For this, I have a huge refugium where I will gravel vac their tank into. The refugium is more like a hitchhiker tank though. It's a brackish 10 gallon at 1.019-1.021 (26-28ppt) and has live rock, some hermits, an emerald crab and some sort of macroalgae that looks like seaweed but small and it bleeds this yellow goo when you break it.

The intention is during low tide daytime, I take half their water and put it in the refugium that is running a filtration system and a flow that keeps all the seaweed flowing very slowly. it exposes the sand and allows them to come out of the water and they love to chill outside the water if its too warm. At night I put the refugium water back in to simulate high tide. I kickstarted my tank with live sand/rock/ammonia then added plants and waited 3 days. first day ammonia was stressful, next day nitrites went up but not a dangerous amount and ammonia was not present. I put small amounts of food in to rot to keep ammonia going because I had no livestock as well as gravel vacuuming waste from their tank. The macroalgae is growing green and fast so I assume that everything is being used as soon as its being made. 3rd day nothing. no nitrates, ammonia or nitrites and my ph was going up so I held my breath till I couldn't and blew my Co2 into the water and that fixed it. (that's when I added some current and flow into the tank.) On the 7th day when the ammonia and everything kept reading 0, I went and got some inverts to clean up and a pin cushion urchin too though it doesn't move much.... I'm looking for really good filtration to get rid of all the food waste without the need to vacuum. I want to put more scavengers to feed off the food the crabs don't. I'm getting a bloom of zooplankton or copepods because the water has a bunch of swimming squirts as well as white stringy gunky growth on my plants.

So my questions are:

1) What is the white gunk and how do I slow/stop and further prevent it? (without water changes. The goal of all this is to fix and balance)

2) What reefmates can go in my scavenging refugium? (they need to tolerate lower salinity)

3) Would a live sponge or sand sifting seas star be good for the refugium for filtration as well?

4) copepods and amphipods...What will control these before they destroy my tank by overpopulating?

5) Corals are on my list of stuff I wanna grow and put back into the ocean when we clean it/stop polluting it, What are some good starter hard corals?

And heres a horseshoe crab horsing around with a toy. (Glass ball filled with shrimp. Puzzle toy)

 

[ichthyogeek]

So while your intentions are good, I have to say that your future actions (not current, present actions) may be illegal or downright unhealthy for the environment. Captive breeding programs for release are best done by zoos and other public animal facilities, since they're able to maintain studbooks with hundreds if not thousands of animals which helps to maintain genetic diversity. Additionally, the release of animals after they have been kept in captive aquaria, has the potential to release disease into the area of release, since the organisms in question are put in contact with a multitude of other organisms. Case in point, you don't mention what species of horseshoe crab you have. If it's a Pacific variety, then your project is already headed towards failure, since you're using Caulerpa prolifera (the small macroalgae that looks like seaweed), an Atlantic macroalgae. Any disease the Caulerpa brought in, may be sustained by the horseshoe crabs. Similarly, unless you directly sourced the crabs and other livestock from the type location, you don't know if they've come in contact with animals that aren't from the type location, such as in an LFS, where fish from the Atlantic and Pacific are commonly mixed.

Your intentions are noble, and for that I applaud you. But releasing animals into the wild with good intentions, is historically a Really Bad Idea (see: european starlings) without a lot of professional oversight. Accidentally releasing them is also a bad idea (see: lionfish, Caulerpa taxifolia)

 

[ichthyogeek]

Furthermore, as somebody who worked in an IACUC and AAALAC accredited lab, I take exception to the common notion that animals are mistreated in labs. Yes, some labs are incredibly inethical and should be shut down. But animal care and welfare is an ongoing topic of discussion to keeping animals healthy and appeased (the word "happy" is an anthropomorphization, which implies that animals have feelings just like humans...which can be widely inaccurate). My lab took great care to keep our fish in an enriched environment, and they were fed food on par with the most spoiled fish in aquaria (they rarely got flakes; I made them a gel food diet, hatched out brine shrimp, culture blackworms/grindals and micros).

 

[ichthyogeek]

Ok, now to answer your questions:
As somebody who has not worked with horseshoe carbs, have you ascertained that you do in fact have at least one male and one female in your crab population?

I recommend removing those rocks from the refugium. It looks like you're going to rely on sand for biofiltration, as well as Caulerpa for waste product uptake. A protein skimmer would be great to add as well. The rocks would only get in the way of the Caulerpa's reproduction (it prefers to spread in sand as opposed to rock)

If you're attempting to simulate tides, remember that it's two high tides and two low tides a day. A gravel vacuum works, but it's best to automate this process.

While holding your breath until you can't is a great way to make your body build up more CO2....in the future you should instead just use an airstone.

Ok, now to answer your questions:

1) You're going to have to do water changes. Biospheres only work for a short while, and the concept of contained life is flawed, as oxygen is used and carbon dioxide is released into the atmosphere ( and where do you think the carbon from the carbon dioxide is coming from? The answer is from the food the hermit crabs eat). There will also be a buildup of waste metabolites over time (not just nitrates and phosphates), and minerals (such as magnesium) will be lost over time. The white gunk on the Caulerpa is just a biofilm. It will go away in time, but you can hasten it by gently rubbing it off of the Caulerpa with your fingers.

2 and 4 ) Your best bet would be to have 1 molly (preferably male), and a colony of small guppies. They are euryhaline fish, and can withstand a lot of changes in salinity. They're also quite good at picking off smaller copepods, and feeding on the food scraps the hermits leave behind. Excess guppies may be sold to the nearest LFS.

3) Sand sifting stars work by destroying the microfaunal populations and eating them. And sponges, while fun, are not the most ideal. If you want to focus on reducing the number of water changes, you'll want to work on maximizing the growth of the Caulerpa you already have.

4) Amphipods: guppies and the molly will pick off the smaller amphipods, but remember that the population can only grow as large as you feed it. The horseshoe crabs will eat most of the food hopefully. The guppies, molly, and hermit crab will pick off the majority of the remaining. Anything leftover (crab/fish waste, excess food) will then be consumed by the amphipods, which will use that to breed. My recommendation is that you bag them up into lots of 100 if you ever get a population boom, and then sell them to people with dragonets and benthic grazing fish like dwarf angelfish.

5) Please see my post on why it's a Really Bad Idea to reintroduce animals willy nilly into the ocean. If this is something you want to pursue, I recommend looking into Jamie Craggs' work (Horniman Museum, he works predominantly with SPS)

 

[sagedrake690]

I'm aware of the crabs origin. some place called aquascape nursery; some site called rusalty based in Florida. The crabs came from the keys (or captivity in that area). I have no idea about the legality of releasing horseshoe crabs and I would have to take that up with the wildlife department of the sate 10 years from now when and if they do breed. As for disease, everything runs that risk when you're adding any sort of livestock to the tank or even getting any sort of debris in there and the same conditions are in a lab as they are in a home aquaria. sometimes home aquaria is much cleaner. I'm certain they check the animals to ensure they are safe before releasing as well.
I'm a student at UCO in biomedical program and I have my nuisance control operator license so I'm not toootally naïve on the process of releasing animals. I was just asking for some advice though, If you have any that will answer any of my questions that would be super! Pertaining to the macro algae, it was only for oxygen and nitrate removal. I feed them a specialized diet recommended to me. It consists of shrimp pellets with higher copper content and algae wafers with brine treats and freshly shredded shrimp on the occasion. However, I got in contact with another biologist while I was waiting for this to be approved and he gave me a thumbs up on the sponges. I went out and struck a deal! A live rock with coralline algae and yellow sponge! It also had 2 different species of coral starting to grow, all only for 8 bucks!

Any idea on the species? I have no idea and neither did the shop owner. As for the feelings part; Yes, all creatures have a form of consciousness. Crabs respond to pain and even form an experience around the object that caused it. Why else do my crabs push rocks with no outcome to it? one crab prefers to burrow under a specific rock and when I propped it up, he knocked it down and burrowed under it. Fruit flies and other seemingly automated arthropods exhibit pleasure, fear and even empathy. Hermit crabs are quite social no?

 

[sagedrake690]

thank you for the response! Someone suggested mollies but I never thought the fish would do so much! It looks like a sand star and the mollies are my next go to. As for the releasing of the crabs, I would most likely give them to a conservation agency before they hatch so they have less of that risk as well. I was throwing around an idea to breed populations of wild fish in captivity to stop the mercury and toxicity uptake in fish populations, But that requires us to clean our water or it does nothing. Basically you're raising wild fish in a clean environment to stop the heavy metals from accumulating and passing on. Over a few generations the fish should be clean and safe to eat again. Our planet is gonna die by 2050 I figure we all need to do something. Aren't aquarium hobbyists basically the arks of the reef world? If they go extinct in the wild we still have them but we cant put them back untill we clean up our act. =/

 

[sagedrake690]

I ordered some eelgrass as well when I bought my rock so I would have a fast growing grass that would suck out more nutrients and have deeper areas for food to decay. I also have a small ferrous oxide stone to help remove excess phosphates to prevent algae blooms.

 

[ichthyogeek]

thank you for the response! Someone suggested mollies but I never thought the fish would do so much! It looks like a sand star and the mollies are my next go to. As for the releasing of the crabs, I would most likely give them to a conservation agency before they hatch so they have less of that risk as well. I was throwing around an idea to breed populations of wild fish in captivity to stop the mercury and toxicity uptake in fish populations, But that requires us to clean our water or it does nothing. Basically you're raising wild fish in a clean environment to stop the heavy metals from accumulating and passing on. Over a few generations the fish should be clean and safe to eat again. Our planet is gonna die by 2050 I figure we all need to do something. Aren't aquarium hobbyists basically the arks of the reef world? If they go extinct in the wild we still have them but we cant put them back untill we clean up our act. =/

While your thinking is great, I think there's a better way. First is stopping mercury and other heavy metals from bioaccumulating into the fish. Policy changes, better waste management policies, and other options are far, far better than a one person mission to reduce bioaccumulation. Unless you were to get hundreds of people to raise wild fish in a clean environment, it's like adding a raindrop into the ocean to lower the salinity...

Also, unless there's a paper I'm not aware of, I only thought bioaccumulation was in single fish, not throughout genetic lines? So again the better thing to do is to focus on stopping toxins from getting into the environment in the first place.

 

[sagedrake690]

Well it is through the individual fish but can pass onto offspring during egg development leading to an already mercury stocked newborn fish. Overall this is like you said, a second step large scale operation involving conservation departments.