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Typus shrimplets


Matuva

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That's a question I'm always wondering about: do the typus hatch juveniles like Neo, or do they release larvaes (Zoe) which would need brakish water to develop?

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They hatch as planktonic zoe which can be raised in estuarine salinity green water but some will make it through in fresh water in your tank.   I've had 20 or so adults for 12 months and there are at least 5 more juveniles in the parent holding tank.

I've had some success rearing the zoe in salt water, but they are difficult and many attempts fail to raise any (all die) because the  phytoplankton isn't right (or starts OK and then changes before the juvenile shrimp settle which takes 30-60 days.

link to pic of typus zoe:

IMG_0548.JPG

Edited by NoGi
Fixed image embed
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Thanks Grubs.

In my typus tank, I have seen hundreds of what I identify now as Zoe, similar to the ones you linked, but not a single juvenile.

Looks more clear to me why now ;)

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Not sure if you guys already know: egg size and number of eggs of species indicate the early life history. Very large and few eggs indicated direct or abbreviated development ie. zoeal stages in the egg. Very small eggs mean lots of zoeal stages spent in the water column. These are hard to rear to juveniles. Often zoeal stages 4-6 are the most sensitive and will die if salinity and food are not appropriate.

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@ura, that's great info to know. I'd love to breed natives at some stage.

@Grubs, thanks for the heads up regarding images not embedding. Will chase this up.

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  • 4 weeks later...
  • 2 weeks later...

Completing the circle

These typus are from my first successful rearing.  They  hatched as larvae in mid march 2015 and reared in salt water until mid april 2015.  Over the winter they have matured and grown in this fresh water tank.  the biggest is now ~25 mm long and there are still a lot of 15mm individuals in the tank (growth rates vary a lot).

Today I saw one of the biggest, now saddled for the first time females "perch" by hanging off a piece of plant - the boys came swarming until they knocked her off the plant and they all fell to the bottom in a mass.  I'm assuming one male at least tried to mate with her.

Its the first time I've seen what looks like obvious mating behaviour in these shrimp.  I got a fairly poor phone shot as the action was far back in the tank.

20150827_115210.jpg

 

three males on her back dragging her off + one to the right.

20150827_115213.jpg

fell to the ground.

20150827_115242.jpg

Edited by Grubs
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And 24 hours later she had lowered the load!

 

20150828_132648.jpg

And from the parents of this lot... today I just completed the migration of my 2nd successful rearing into fresh water.  The first successful batch is what produced ^^ those.  The hit rate isn't very good. That is 2 out of ~15 attempts (each taking 4-6 weeks) that have produced a significant number of juveniles.  Other times they all die or I get less than 10 survive.  From here they get tipped into a tank of 60-100 litres and it will take 5-6 months for them to grow to maturity as I've just found out ^.

20150829_134202.jpg

Edited by Grubs
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Great to see and fascinating to see that your having some success. Have you tried raising the zoes in brackish or just straight into Im guessing ocean/ beach saltiness?

I'm wondering if you could get some mangrove mud for the zoes if they might have a better survival rate, in the hope that the mangrove mud might have some mircofoods that the zoes particularly need in order to grow.

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I've tried the full range from fresh to 35ppt.  This batch was ~24ppt.  Previous success was 28ppt. Not sure that mangrove mud would help because the planktonic larvae spend most of their time mid-water.  I've watched them with a magnifier and they generate a feeding current with their legs and pull in suspended algae cells.  What makes it hit-and-miss is the algae culture needs to be maintained for over a month for the shrimp to complete the planktonic phase and settle.  Often they start out well but the cultures run off on a weird tangent for unknown reasons, good algae get replaced by bad... or the water clears....  or BGA gets a foothold... or the green culture goes brown... or...it gets too salty from evaporation and the algae dies... or something else!  Its an exercise in persistence as much as anything.

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