Shrimp Acting Strange After A Water Change

[stubzy]

hi, i am new to shrimp, i have had 20 red cherry shrimp in my aquarium for about a week now, and just done a 10 litre water change in a 55 litre tank, a friend told me to add the clean water as slow as possible, so i have used a bit of air tubing to syphon the water back into the tank, took roughly an hour to get 10 litres back into the tank. the water going back in are the same perameters as the water in the aquarium, temp and ph etc.
 
The shrimp have been fine for the week they have been in my aquarium, grazing on my plants (they made my tank totally spotless in a day, was incredible how good these guys are at cleaning), to the point, during the water change i have noticed that most of the shrimp are swimming around like mad, swimming around after each other, i have not seen this behaviour before, is this normal after a water change, is it a good sign or a bad sign? any input would be great, thanks.

 

[Mamashack]

They are brilliant at chomping away aren't they?
Did you have the filter switched off during this hour it took to refill the tank? If so it may be that they were suffering from lack of water movement ie oxygenation was reduced and toxins may have built up in certain areas.
You could try running the replacement water against inside of the tank wall if you want to reduce any turbulence. An hour is quite a long time to be refilling.
I have shrimp in both my tanks and I replace about 15-20L every week in the 60L in a few minutes. When doing both my tanks' maintenance I try to keep the power off as little as possible - probably 10-20 mins max. every week.

 

[stubzy]

yes the filter was off during the water change, i dont think its a shortage of oxygen though, the tank is very well planted and has a full HC carpet that pearl about 30 mins after lights on, meaning the water is oxygen saturated, its now about 2 hours since water change and they seemed to have settled back down now and are all happilly grazing again. They mite have just got excited to have cleaner water in the tank. will see if they do it again next week when i do my weekly wc

 

[Baccus]

I would say it was just excitement about the new water, water changes can encourage shedding and if one of the females moulted then the males might have gone crazy looking for the female that was ready to breed.
If possible I would leave the filter on during water changes or at least while you are refilling the tank.
For my really sensitive shrimp ( not my cherry shrimp) I prepare their exchange water at least 2-3hrs before doing the water change but preferably a day or two before hand. This entails having a tub of new water with declorinator added and then running an airstone in the water to help any chlorine neutralise and spread out the declorinator. The water I then added back into the tank with a small container.  Since carrying out this type of water changes I have not lost any of my really sensitive shrimp and have had quite a few of their offspring survive with more generations on the way.
The biggest threat to the shrimp is pH and temp changes with water changes so if these are controlled then water changes can be pretty straight forward and less time consuming.

 

[stubzy]

i cant really run the filter while doing a water change, its an aqua nano 40 tank so the whole filter is part of the tank, and the inlet outlet of the powerhead cant be moved