floating nem

[jjb]

over the last week my purple bubble tip nem has inflated itself to the size of a small football and floated around the tank ,this only seems to happen when the lights are off (hence the post at this time in the morning).

when the 1st stage lighting comes on he sticks back onto a rock that he has found and over the day he shrinks back into the rockwork as if nothing has happened.

this is the nem that split into two about 3weeks ago if that has anything to do with it.

its clone was given away as not to have 3 nems in the tank .
there is a 2 year old green bubble tip on the very top of the rockwork which is host for my two clowns and is very happy.

any idea,s as will sort it when i get back after work.

[Tony B]

A happy nem is unlikely to do that, splitting can often be associated with stress too.

What are your water params?

How stable is your temperature and salinity (do you use an auto topup?)

[jjb]

my parameters:

ph. 8.2
salinity 1.026
temp 26 (static as chiller used)
phos 0
nitrate 0
nitrite 0
calcuim 420

hope all is well

the only thing i have changed is the lights from a acardia 2x150w+30w actinics to a gueisman 2x250w+4x54w actinics(2 blue 2 white)

[Tony B]

All the params you list are fine....

Alkalinity?

Have you measured your PH at night? Could there be a swing in PH?

Do you have an auto top-up to replace evaporated water?

[jjb]

alkalinity 7 dkh

not done a test a night will try tonight. will post if it all start going wrong

the water is topped up by a tunze osmolator .

[Tony B]

Your DKH is OK but a touch low; this (combined with a loack of gas exchange) could be causing a PH swing when the lights go out.

I'll be interested to hear what your PH is after the tank has been in darkness for 4 hours, and after 8 hours.

[Tony B]

Did the nem do this AFTER you changed lights? Was it not floating BEFORE the change of lights.

To be fair, that's quite an upgrade in lighting - did you start with your lights nice and high above the tank then slowly lower them?

[jjb]

will let you know results later ,

thanks for your help

[Tiggsy]

would a light upgrade not encourage hiding in the rocks as opposed to floating off which sounds like a "i want to move outta this place" reaction as opposed to "ohhh, its a bit bright"

[Tony B]

would a light upgrade not encourage hiding in the rocks as opposed to floating off which sounds like a "i want to move outta this place" reaction as opposed to "ohhh, its a bit bright"

I see your logic Tiggsy. Both actions would indicate a problem with it's current environment. What action the animal chooses and then linking this to a cause is another matter and I dare say, would be guess work (I am unaware of any credible studies that have been done to establish what reaction corralates to what stress factor). Although, I could be wrong ;)

[Tiggsy]

I am unaware of any credible studies that have been done to establish what reaction corralates to what stress factor

When i upped my lights to 250 watts my nem looked like it was thinking "ohh, its bright here" - not a credible study as such.....but very close :D

[Tony B]

When i upped my lights to 250 watts my nem looked like it was thinking "ohh, its bright here" - not a credible study as such.....but very close :D

When I done the same from t5s, my nem moved right up and was directly under the 250w bulb

[jjb]

the ph drops to 8.1 after about 4 hours when the lights are out and seems to stay there.

[bristlebasher]

I think it is a stress response to the change in lighting - and as said - determining what that response will be is difficult. The nem is obviously not happy and now doing it's damnest to find somewhere else to live. Keep an eye on it - if it refuses to settle then find another home for it I'm afraid. Please make sure that there aren't exposed powerheads in the tank that it could get sucked into.

[jjb]

thanks
there is no problem with power heads all closed loop with filter foam so he should be ok .he seems to have settled on a rock in the middle of the tank, and has been there for a day and is fully open and looking heathy fingers crossed.