RE: Yamato Shrimp behavior

["Joe Kopanski" <kopanski at earthlink_net>]

> This time I am determined to keep them healthy. Stopped the
> algaecide for good. Just put in 20 Yamato Shrimp into my
> tank. Watching them very closely for any distress signs.
> When the lights are on, most of them will stay as a group in
> the corner of my tank. Is this normal? Are they nocturnal critters?
> All advice is appreciated.
>
> Wayne Wah from Singapore.
>
I don't know if this is normal but my first batch of Cardinia Japonica did
exactly the same thing, but when the lights were *out*.  They packed into a
corner so tightly I was concerned about the ones at the bottom.  I had three
theories:  1) It was a protective maneuver (The poor little guys were
scared.)  Maybe one shrimp looks like dinner, but 25 in a mass look like
something you don't want to mess with.  2) My water quality was so good that
it triggered some sort of mass mating behavior.  3) My water quality was so
poor, or at least different, that the shrimp found this particular corner at
the bottom of my tank the least offensive.  I prefer theory 1, that they
were basically in shock - some fish act strangely for a couple of days after
any transfer.  My shrimp stopped doing this after about a week.  They seem
to go through phases where they are more or less visible in the tank.
Usually a good feeding of algae tabs will cause them all to disappear for a
couple of days.

Specifically for the shrimp, I add seachem reef iodide (1 mL per gal) at
water changes and add either a calcium carbonate tablet of CaSO4 chunk every
week.  They do eat the calcium carbonate (you can see the white moving
through their digestive tract) and it seems that sheddings occur more
frequently afterwards.  If these additives are truly necessary, I do not
know for sure, but my shrimp have been very healthy for 16 months.

For the person looking for a mail order source.  Arizona Aquatic Gardens and
Florida Driftwood both offer them over the web.  Mine shipped flawlessly
from AAG.  The problem with mail order is that shipping will cost as much as
the shrimp.  Maybe post your general location and if someone sees them
locally they can let you know.  I've driven a 100 miles for a specific fish
myself.

Joe K