Shrimps and fish fall-in forming contingent at the surface of water

[Cyberkinetic]

Hi all,

I did some maintenance of my 10gallon tank yesterday by trimming away all the plants/leaves which are infested with black hair algae. Quite a significant trimming and subsequently did a 10% WC.

Things looked normal until some time around 11pm, when I went near the tank to shine a light on it as what I usually do just to check it out before heading to bed, I got a big shock when I found that almost all of my shrimps, probably >50 malayan and >8 Sakura all clinging onto the plants which are at the surface of the water. The plants were literally covered by shrimps! And I also realize that my platys and rummynose tetras are quite active(strange at this time of the day where they are usually quite slow moving). And they are also heading up and down the water surface. I was shining the torch at the bottom of the tank.. there were not a single shrimp there... it's as though EVERY shrimp left the bottom and went straight up to the top.

First thing that came to mind is the lack of O2... I wondered if the trimming of the plants reduced the O2 contribution and also as I've added 10 sakura and 8 rummynose recently, not to forget the forever breeding platies(which I gave up trying to scoop the babies out after couple of attempts.. I counted at least 8-10 babies and about 4-5 juveniles), I think the O2 balance might have just tipped over now.

So I quickly took out the old standby airpump and put in an airstone and powered it up. Due to all the activities on the tank, some of the shrimps left the plants on the surface while some, notably the Sakuras are still hanging on there. Kept monitoring them until around 2am... and things seemed to be back to normal.

This morning, checked out the tank things seemed to be ok as well. No fish or shrimp death that I can observe and no gathering at the surface as well.

Just wondering if my deduction of the O2 level is correct and should I leave the airpump running or just switch it on at night and off in the daytime as I've seemed to read somewhere before. I had an extra timer switch which I had bought previously when I switch to my canister filter thinking I will need to add an airpump but didn't seemed necessary then until now. Or is there any other issues which I may not be aware? Water condition as far as nitrate/nitrite and ammonia is concerned, it's all ok. Platies are breeding, plants growing well and I also found some shrimplets(probably the Sakuras since there's 2 heavily berried ones of the 10 that I got) a few in the tank and at least 2-3 at the bottom of the Eheim filter(used to be just seed shrimps populating that area but found the shrimplets yesterday when I shined my torch there).

I will try to upload photos of my tank from my phone later... to show the amount of vegetation that i had trimmed off...

Thanks for any advice to be given.

[tetrakid]

In my fish-keeping practice, I always give top priority to good oxygenation, especially via surface agitation.

Whatever type of filter is used (be it hang-on, canister or top), it is important to ensure that abundant (at least 8ppm) oygenation is present. Not only fish enjoy oxygen, but also the other live organisms such as the bacteria on the media. By all means add CO2 for plants, but definitely not at the expense of lower oxygenation.

[Cyberkinetic]

This is better trimming(taken a week ago):

This is after trimming.. My water onion almost bald.. Trimmed the grass at the back as well. I would've thought the rotala stems which grew sooooo fast would make up for those that I trimmed off..

[felix_fx2]

Your "lalang" very tall now hehe
If you have large trimming session is like that one. Also notice that with my tanks.

So far have been no deaths.

Sent from my GT-I9300 using Tapatalk 2

[Cyberkinetic]

That's good to know Felix... But for safety sake.. i think I'll leave the air stone running at night for the next 1-2 days just in case..

The "lalang" is really getting to bother me.. I have to cut them every two weeks.. only managed to give out one batch cos subsequent ones, due to the algae thingy in my tank, I dare not offer it to anyone in case it spreads to them. So I'll selectively pick those existing ones which looked sickly with black stem and replace it with the new cuttings.. it's like a never ending job...

Hi Tetrakid,

how do you measure the oxygen level in the water? Do we get a test kit similar to those for ammonia, nitrate and nitrite? I set the outlet from my canister under the water level as previously when I tried to put it above, water was splattering all over my lights and out of the tank. This is probably another option for me to do again if I don't want to use the air stone. Thanks.

Cheers.

[tetrakid]

Hi Cyberkinetic,

Strictly speaking, there's really no need to measure the the oxygen level in the water column. As long as one pays more attention to oxygenating the water, the behaviour and disposition of the fauna itself is a good measure of the oxygen level.

Surface agitation is the best way to ensure adequate oxgenation (either in a sump or on the tank surface itself). Canister filters without a sump are often problematic in this regard, as many hobbyists simply let the water flow back into the tank via the return outlet pipe or hose. The best way is to utilise the return water flow by using it to agitate the surface OVER A LARGE AREA. Attaching a well-designed spray bar is superb for this purpose. To maximise oxygenation, it is important to continuosly break as big an area of the water surface as possible (by lateral agitation). Thus spray bar positioning at the water surface is important.

Though an air line does somewhat mimmick the surface agitation action, it is not as efficient, and gives rise to noise and splashing problems.

[felix_fx2]

Change them
It is a never ending thing.

[Cyberkinetic]

For the second time, I realize the same behavior after I chomp off large parts of the plants... Just wondering if it's due to the "sap" from the plants which flood the tank after I did the trimmings?

Could that be the issue? Confirmed, stamped and chopped it's related to me doing tank maintenance of trimming the plants.

They will act this way for at least 3-4 days before things go back to normal.

[nickel]

I observed that same life stock behaviour after trimmings. I also think is due to the sap being released into the water after trimming oof plants.

I will do a partial water change after trimming and observed only some fishes still like that while others not so.