[Cuttlefish Eggs]: Ray's 125G Cuttle Rearing System

[DWhatley]

Are your red volcano shrimp reproducing? I bought some to try to establish a breeding colony. They are growing and surviving but don't seem to be reproducing. Suggestions?

 

[magnetar68]

No, I have not seen any offspring. I have had mine in a 2.5G tank for 9 months. While they are about the easiest creature to keep, they are difficult to breed. According to Pete Giwojna of Seahorse.com, Halocaridina rubra need a salinity 1.0114 S.G. a temp of 72-73F and less than 10ppm Nitrates. They reproduce slowly (large females only carry 12 to 14 eggs at a time). They spawn but 4 or 5 times each year, and produce an average of only 5-10 larvae per spawn. They can, however, live for up to 20 years

From Pete's Book: "The larvae hatch as free- swimming, yolked zoeae after a brooding period of 38 days...[Light] triggers their four-stage larval development. Larval development is abbreviated with four zoeal stages and one megalopial stage occurring before they reach the first juvenile stage. The larvae retain a large yolk sac when they hatch, and this yolk supply is sufficient to sustain them throughout their larval development. The larval volcano shrimp normally do not feed until becoming benthic post-larvae (i.e., miniature shrimp). This transformation takes only a few days, during which the surface-swimming planktonic larvae metamorphose into post-larval shrimp, and these juvenile shrimp then settle down to the bottom and assume a benthic way of life like the adults. The newly transformed juveniles are 3-4 mm in length and look like miniature versions of the adults, except for their large eyes. (Due to their underground habitat, the eyes of adult volcano shrimp are greatly reduced and all but unnoticeable.) The juvenile shrimp gradually lose their well-developed eyes as they pass through a series of molts. In the aquarium, it takes about 24 to 27 days for the young to complete their development and become mature adults at 22°C-23°C. (Note: the development of the planktonic larvae from one stage to another, and their transformation into benthic juveniles cannot take place in freshwater; rather, brackish conditions are required for proper larval development and metamorphosis.)"

 

[DWhatley]

Love Pete. I was aware of the longevity and low egg count (and why I am starting the culture without a need) but it looks like I should try lowering my salinity. These were fairly young when I got them and have doubled in size so maturity may play a roll as well. There are brissle worms in the live rock that I hope are not eating eggs. The person I bought them from mentioned the shrimp laying eggs in the rock but I question her knowledge of this behavior as I believe the eggs are carried like other shrimp. If they do deposit eggs, the worms could be a problem.

 

[magnetar68]

Pete also recommends using lots of volcanic rock to build them their natural habitat with lots of small little dark crevices and caves. They need dark places to breed and prefer this. He recommends a dark end of the tank and a light end where some algae can grow.

 

[magnetar68]

I built this critter keeper-based, higher flow container. I got the idea from Richard Ross's article here. The hope is that the higher flow environment will keep the frozen mysids moving and therefore make the frozen food a more interesting target. The cuttles are only 24 DAH, and most of them seem more scared of the PE mysids then attracted to them (perhaps because the PE mysids are so large compared to them and their current live mysid food). I tried this last night with a smaller mysid and one of the cuttles did eat it as the frozen mysid moved back and forth on the gravel in the flow.

Here is a video update as well:

 

[DWhatley]

The person who cultured these mentioned egg laying in the rock but I suspect she meant breeding and I don't see them even particularly close to one another in the tank so adding rock may be helpful. I have some that that I use in my crab tank I think is "natural". It has been carved for aquascaping and is it a red color so I am not sure if it is natural or artificial. I think I will look for it on-line to see if I can determine it origin.

 

[magnetar68]

I found this online here. It seems directionally correct. I might move the few remaining H. rubra over to a 10G to see if I can get them to breed.

Lastly, I remember suggesting here that my success in getting my opae ula to breed were due to 4 things:
1. Proper water salinity and temperature. (I forgot exactly what they were. I have them written down somewhere)
2. Adequate food supply, which was twice weekly spirulina powder mixed into cold spring water and poured in, and algae growing on the glass wall of the tank.
3. Plenty of dark, interior space formed by live rock, for them to hide. In the wild, this is their natural habitat. It just doesn't seem natural to me to place them in a tank where they're out in the open with no place to hide. They need that, especially berried females.
4. Regular water changes. I know a lot of people say you don't need to, but I had great success in doing a 1/4 tank water replacement every month. I think it mimics their natural habitat, because water levels and salinity changes often in those pools, especially during rains. I think a surge of fresh brackish water with feeding mimics tropical rains bringing food to shrimp in the wild and triggers an urge to breed.

 

[DeepBlueWonders]

Looks very nice! I'm really liking the set up. There may even be too much flow in there for the cuttles. You might want to either lower the flow rate, or provide more macro algae for them to hide in.

 

[DWhatley]

I am feeding more than the forum suggests but the original seller fed daily and my experience with getting peppermint shrimp to spawn suggests feeding more, not less is bneficial. I mix spirulina power in with crumbled flakes containing the same algae. They are definitely eating the flake crumbles and algae on the sides of the tank. I am going to give my current set up another month but lower the salinity. The shrimp have doubled in size so they may just be too young. If I don't see mating (i.e. shrimp with eggs) in Feb. I will hut up some lava rock to add to the existing oolite but the rock I have offers crevices and darkness and I don't light the tank (but it does receive daylight from windows).

One oddity, is that they swim most of the time (they are in a biorb without the filtration and an outer ring of air bubbles) The original supplier said hers often stayed in the rock until feeding time and then swarmed the food so this might suggest more rock is part of the key.

 

[magnetar68]

Looks very nice! I'm really liking the set up. There may even be too much flow in there for the cuttles. You might want to either lower the flow rate, or provide more macro algae for them to hide in.

Yeah, I am keeping an eye on it, but they seem to be ok. I was hoping Richard Ross might chime in since he is the one that made the observation that hatchlings do OK in higher flow environments. They all seem to have found a place to hide and they all seem OK venturing out at night despite the flow.

 

[DWhatley]

You might PM Thales with a link in case he misses the post.

 

[magnetar68]

4 Weeks after hatch. I still have 8 cuttles. I fed each one of them a smaller ghost shrimp. They we eager to eat them.

 

[magnetar68]

6 Week Update

It's been a little over 6 weeks and all eight cuttles seem to be doing OK in the higher flow container. At 6 weeks, I moved the cuttles off of mysids and onto common shore shrimp (Palaemonetes Vulgaris). I had a couple of them eating frozen mysids, but the majority wanted live mysids. Earlier, at five weeks, I had tried some smaller freshwater ghost shrimp I got at the local Pet Club. Despite the fact these ghost shrimp were at least the same size as the cuttles, all of the cuttles ate them vigorously. I therefore ordered 250 shore shrimp from www.livebrineshrimp.com. They are in a 20G Long with a thin aragonite base and a sponge filter, heater, and whisper hang-on-the-back overflow with a biobag with carbon. I am feeding them a quality reef flake fish food. I am not sure how many of these large prey I should be feeding the cuttles at this point. Anyone have any tips? I have been feeding one smaller shrimp one day and two shrimp the next day and then starting over with one the day after that, continuing the pattern.

 

[DWhatley]

You might want to monitor your little filter with the shrimp. I have had problems with the shore shrimp being sucked into an even smaller Azo filter so I keep a net around the intake. The holes in your Whisper do look smaller than the slits in the Azo but keep an eye on the filter for shrimp in the wrong place for awhile.

 

[magnetar68]

I have been keeping an eye on it. They seem to be OK. Even the smaller ones seem to be able to walk on it. On my volcano shrimp tank, I cover the inlet with foam. I might do that here just in case.

My bigger issue is nitrates. The sponge filter was seeded in reef tank sump for several weeks before using it here, but after just a few days my nitrates are up to 80ppm. I have been feeding a large pinches of flake food 2x per day. Maybe that is too much? But there are 200+ shrimp in there and they seem to eat all of the food.

I will do a water change tonight, but any other easier ways to keep this low?

I have some Microbacter7 I could dose. I was even thinking about setting up a biopellet reactor on the tank. I can see it with biopellets from my other reactors that are well established (over a year).