First captive C. Clypeatus breeding (2015) english description

Gespeichert von Dany am Di, 01/23/2018 - 09:55

In general:

Larven
This is how little larvae look like (microscope view).

This is a description of my breeding of C. clypeatus. As far as I know, it's the first breeding of this species in captivity in Germany and maybe in the world.

In 2012 a female German crab owner managed for the first time to breed C. vioalascens, and some more in the years after. Then she breeds C. rugosus and C. purpureus in 2016. A Australian crab owner breed C. viabilis several times. About these and my former tries you can read in the HCA-forum and the German forum (Landeinsiedlerkrebs-Forum), which I linked in my site “Links”.

So called breedings, with no proof of pictures or other documents, should be treated as fake news.

My tanks:

Since September my crabs are living in a big self-build tank, which was extended in 2011.

The size of the area (both tanks together) is about 2,4 square yard. The bigger one is about 5.9 foot long, 2.6 foot wide and between 1.5 and 3.9 foot high. This is the "woodland".

The smaller one is about 3.9 foot long, 1.3 foot wide and 3.9 foot high. This is the "beachside". In this tank is a 2.1 cubic foot salt-water tank (15.8 US-gal/ 13.2 UK-gal).

Both tanks are connected, so the hermits can decided, whether they like to stay at beach or in the wood area. In both tanks are small bowls with salt and fresh water.

I use real plants, for a better damp climate, with only one exception. There are other animals, which share the tank: Asian geckos (Hemidactylus frenatus), batik crabs (Metasesarma obesum), and some time ago a pair of halloween crabs (Gecarcinus quadratus).

Breeding:

Acrylglasröhre als Kreisel in einem Aquarium.
Lucite or Perspex tube in a normal fishtank.

To nurse larvae is difficult and needs a lot of time and engagement, because the larvae live in salt water for some weeks, until they get houses and walk onto beach.

The larvae molt several times and this molting, the search for a fitting house and the transition from water to land are difficult phases.

In a small waterbowl they suffocate soon, because of the few oxygen. Of cause the volume of my salt-water tank gifts them a better start.

For the raising of the larvae, I use a separate tank.

Billiger Selbstbau: Keks- oder Fruchtgummidosen in einem rechteckigen Einer
cookie or fruit gum box in a sqared bucket

It seems best for the larvae, if they can float in the water and do not sink to the ground. Therefore Kreisel-tanks are perfect. A Keisel-tank is a round tank, in which the water circulates.

You can make a Kreisel-tank become reality in differed ways. You can use a bucket, cookie or fruit gum boxes to build one on your own. Or you can buy a Lucite or Perspex tube and cover the ends. If you have luck, you can get a glass vase like I did.

To circulate the water I use an air tube. The bubbles rotate the water. Another way to make the water flow, is to use a little pump, but that can be dangerous for the larvae.

To heat the water, it's the simplest way, to put the Kreisel-tank into another tank, in which you heat the surrounding water.

Now I only use the glass vases, got five of them! But I still own the others. Anyway, you never know, how much larvae you get. ;)

Parameters:

Gekaufte Glasvase die sich durch ihre schmale Form als perfekerter Kreisel erwies.
glass vase

The concentration of the salt-water should be between 1,022-1,026. Most likely the same, which you use in your salt-water dish. It's bad for the larvae if the concentration of the salt-water changes.

1.025 is a salinity of 3.5% (35 g/L, or 599 mM).

The temperature should be between between 24-26°C (75.2-78.8°F). In fact, in my last successful breeding I had temperatures some degrees below an above, but those changes had been during a long time period. Because of the hot weather the highest temperature had been 30°C (86°F). The mortality rate is higher the higher the temperature grows. Over a long-term it's better to adjust the temperatures I mentioned in the first line.

In earlier tries I used light in the night, to prevent the larvae from sinking to the ground of the tank. But since the rotation in the glass-vases are nearly perfect, I didn't use an extra light in my last tries.

Artemia zwischen LEK-Larven
hermit larvae with larvae of brine shrimp

I feed the larvae form my hermits with freshly hatched larvae from brine shrimp (Artemia salina).

With clear salt-water you should daily change 20-50% with new salt-water, because it's getting dirty very fast. In clear salt-water should not be more than 50 larvae per liter.

Using algae like Nannochloropsis salina in a higher concentration (the water look green) helps to stabilize the water. The amount of larvae can be much higher and the period in which the water has to be refreshed is much longer.

But anyway, it's always good to know the exact water-parameters and use regular tests for fish-keeping.

Development of my larvae (trial 10):

Day 1 (07|25|2015): approximate 15.000-20.000 larvae

Day 7: high loses in the clear salt-water, still approximate 15.000 larvae, most of them in stage zoea 2

Day 10: stage zoea 2 and zoea 3, about 12.000 larvae

Day 13: stage zoea 3 and the first zoea 4, about 9.000 larvae

Day 16: first zoea 4, about 8.000 larvae

Day 18: first zoea 5, approximate 7.000 larvae

Day 20: first megalopa - unfortunately dead!

Das Riffbecken (Sand, Muschelkritt und viele kleine Schneckenhäuser)
The reef-tank (sand, shellpieces and small shells)

Day 21: counting the larvae of two tanks and estimated those of the other tank: still 5.000 larvae, 5 megalopas moved to the separate reef-tank.

Day 22: 13 more megalopas

Day 23: 21 more megalopas

Day 24: 40 more megalopas

Day 25: 45 more megalopas

Day 26: 63 more megalopas

Day 27: 15 more megalopas (together 202 so far), still 2058 larvae left (counted)

Day 28: Now the new megalopas stay in the Kreisel-tanks. First megalopas are interested in shells/houses.

Das Übergangsbecken
transition-tank

Day 37: 3 megalopas in houses transferred to a water-land-transition-tank

Day 38: One animal seen on land! 23 more megalopas in houses transferred to the transition-tank. All megalopas from the Kreisel-tanks moved to the reef-tank.

Day 39: 12 more megalopas in houses transferred to the transition-tank.

Day 40: 3 more megalopas in houses transferred to the transition-tank.

Day 41: 8 miniature-crabs, which stayed on land, transferred to a separate small tank. 3 more megalopas in houses transferred to the transition-tank.

Day 42: 12 miniature-crabs, which stayed on land, transferred to the separate small tank. 4 more megalopas in houses transferred to the transition-tank.

Day 43: 3 megalopas more megalopas in houses transferred to the transition-tank.

Day 44: 2 miniature-crabs, which stayed on land, transferred to the separate small tank. 4 more megalopas in houses transferred to the transition-tank.

Day 45: 3 miniature-crabs, which stayed on land, transferred to the separate small tank. 1 more megalopa in a house transferred to the transition-tank.

Day 46: one miniature-crab, which stayed on land, transferred to the separate small tank.

Day 47: 3 more megalopas in houses transferred to the transition-tank.

Day 48: 4miniature-crabs, which stayed on land, transferred to the separate small tank.

Day 50: 2 more megalopas in houses transferred to the transition-tank. 2 miniature-crabs, which stayed on land, transferred to the separate small tank.

Day 52: 1 more megalopa in a house transferred to the transition-tank.

Day 54: 2 miniature-crabs, which stayed on land, transferred to the separate small tank. 1 more megalopa in a house transferred to the transition-tank.

Kleines Terrarium
small tank

Day 55: 3 miniature-crabs, which stayed on land, transferred to the separate small tank. 1 more megalopa in a house transferred to the transition-tank.

Day 58 (09|21|2015): One last megalopa without a house (!) transferred to the transition-tank.

Total all for now: 40 little crabs on land and at least 8 in the transition tank.

10|20|2015: Still 24 little hermits are living on land and develop well.

11|25|2015: It's certain now, they are C. clypeatus (PPs, Purple Pincher)!

02|13|2017: After al long time in the small tank, the first 23 crabs are now in al bigger much tank (2.6 foot long, 1.3 foot wide and 2.6 foot high). While transferring them I made some photos.

02|20|2017: Now two more crabs are in the bigger tank. So there are still 25 of them!

Umzug
Some of the hermits while transferring them to the other tank.
Registrierung
Documenting the size of the crabs by now.

07|25|2017: Happy birthday! Second birthday of the crabs. Still 25 of them!