RCS intermittent lethargy - warning or benign?

[libertybelle]

Background: I posted here over a year ago. I got a batch of RCS from someone on a forum, they did very well and reproduced like crazy then started dying off one by one over a long time. Mustafa suggested a chloramine problem so I started double dosing prime (though I never did find a chlorine test kit at my local stores to confirm.) Unfortunately that didn't seem to help and over the following weeks the rest of them died off at a very slow rate. I suspected something had changed in my source water and I took a break from shrimp. Recently I saw some in a LFS and decided to give it another shot. More experience combined with (maybe) my water going back to normal over the last 15 months or so...maybe I'll do better this time.

Current tank: I have 4 red cherry shrimp (started small this time) in a 5 gallon hex with an adjustable heater that keeps the tank around 76-78. Had 6 originally but lost 2 within 24hrs of drip acclimating them, a couple weeks ago. But they came straight from the bag they shipped in, so I imagine that was shipping stress. There are also two tiny baby mosquito rasbora in there (Hoping to get a few more, let them grow up a bit then move them to my larger tank) The tank was running as a quarantine tank for a while and the filter media came from an established tank. (sponges and wet/dry bio wheel - standard on the hex.) i checked water chemistry levels frequently when i first added them to make sure there was no mini cycle, and have had no measurable ammonia/nitrite problems. It has a couple clumps of java moss and and an Anubis plant.i have only been running the overhead light for a few hours at a time in the morning and at night because I don't want the tank temperature to fluctuate too much. They are eating leftovers from the small amount of 'first bites' that I am feeding the rasbora 1-2 times daily. Also have put in a tiny piece of algae or shrimp wafer a couple of times to make sure they are getting enough food. I imagine most of their food they are grazing off the java moss.

Concern: I haven't lost any shrimp since the first 24 hours after bringing them home, However, every morning I notice they are not very active- not doing their constant grazing thing. So i do a small water change (usually just a few cups, tap + 1.5X prime usually 'aged' for 12-24 hrs) they perk up, scurry around and act normal. However when I get home from work they are usually still again. Cue another small water change ... Rinse and repeat. The fish have shown no signs of stress at all.

Is it possible that with the plants in the tank and only getting a few hours of direct light in the morning and in the evening, There is not enough oxygen in the water? Would that cause them to lower their activity level like I have noticed. I lowered the water level already to see if that would help but nothing really changed, so that doesn't seem to be it. Or is this not really a sign of stress ... I may be hyper sensitive because I lost the ones I had last time around.

Feel free to offer suggestions or tell me to stop being a worrywart. Either is an appreciated response!

[Mustafa]

Generally speaking, the more you mess with a tank, the more things get messed up. Store-bought shrimp aren't in the best of shapes anyway, so they will be lethargic for quite a while. And most of them will die off no matter what you do. The best thing really is to leave the tank alone and let things happen...I don't know if this is a new tank again or if you used an old tank, but new tanks have to cycle for quite a long time to be shrimp ready (about 2 months).

[libertybelle]

Not a new tank, really. It was up and running as a quarantine/ghost shrimp tank for a couple months, don't really remember how long . The filter media was from that tank and I added some filter media from my other tank that has been running for a few years

[Mustafa]

So, how were the ghost shrimp doing? Are they still around?