Temperature shock after water change - please help!!

[nerdyaquarist]

Hi everyone,

I just did a 30% water change in my 29 gal community tank with 7 gallons of RO water and almost 3 gal of tap. It completely went over my head that the room temperature is currently about 65 F. I noticed immediately after doing the water change that all of my shrimp started coming out and jumping everywhere! All of my fish start freaking out and glass surfing and gathering in the corner. I checked the temperature, and my tank dropped an entire 8 degrees during the change. My temperature is usually about 79 F and my thermometer said that it was about 70-71 F.

I’m really concerned now about my fish and my shrimp. The shrimp have now since mostly stopped twitching and jumping around but are still inactive and look almost frozen. Not all, but many do. I honestly need some reassurance here if everyone is going to be fine or not. And if not, what can I do??
 

For reference, my fish stock is endlers, honey gouramis, and cardinal tetras. The cardinals are the most sensitive and are the fish I’m most concerned about. 

[Jurrian Hering]

Thats definitely not ideal! Ive made a similar mistake in the past. What i did was immediately pull out a chunk of water then change in some warmer water. This brought the tank temp to about 6 under where it normally ran. fish were really stressed out and i did have some shrimp die but overall, most made it. I could see an argument though to not do that to avoid shcoking them again. 

All that to say I'd bet most will survive but some of the weaker ones may not. Hopefully they all make it im sorry that happened!

[nabokovfan87]

On 2/4/2023 at 5:00 PM, nerdyaquarist said:

I just did a 30% water change in my 29 gal community tank with 7 gallons of RO water and almost 3 gal of tap. It completely went over my head that the room temperature is currently about 65 F. I noticed immediately after doing the water change that all of my shrimp started coming out and jumping everywhere! All of my fish start freaking out and glass surfing and gathering in the corner. I checked the temperature, and my tank dropped an entire 8 degrees during the change. My temperature is usually about 79 F and my thermometer said that it was about 70-71 F.

Shrimp being active after a WC is VERY normal.  When it comes to dwarf / fancy shrimp, you do want to try to match temp when doing WCs like this.   Generally speaking 2-3 degrees cooler should be ok.  The heater can rebound things up a bit easier at that point.  If it's too hot, add some ice.  In a pinch, that's how I handle things.

Question.  What else is in the tank?  Is it possible for you to run the tank cooler with the stocking you have?

[nerdyaquarist]

On 2/4/2023 at 5:28 PM, nabokovfan87 said:

Shrimp being active after a WC is VERY normal.  When it comes to dwarf / fancy shrimp, you do want to try to match temp when doing WCs like this.   Generally speaking 2-3 degrees cooler should be ok.  The heater can rebound things up a bit easier at that point.  If it's too hot, add some ice.  In a pinch, that's how I handle things.

Question.  What else is in the tank?  Is it possible for you to run the tank cooler with the stocking you have?

Thank you for the reassurance. I have cardinal tetras, honey gourami, and endlers. I can’t really keep it much cooler due to the cardinals. 79-80 seems to be the sweet spot for everyone. 
 

On 2/4/2023 at 5:20 PM, Jurrian Hering said:

Thats definitely not ideal! Ive made a similar mistake in the past. What i did was immediately pull out a chunk of water then change in some warmer water. This brought the tank temp to about 6 under where it normally ran. fish were really stressed out and i did have some shrimp die but overall, most made it. I could see an argument though to not do that to avoid shcoking them again. 

All that to say I'd bet most will survive but some of the weaker ones may not. Hopefully they all make it im sorry that happened!

I thought of that but I worried about freaking them out more since I was doing plant maintenance before the water change and already stressed them out. I hope not too many of my shrimp go 😞 I have been doing smaller changes throughout the winter to prevent this but I just completely forgot today since it was looking particularly algae-y.

[AllFishNoBrakes]

@nerdyaquarist While I can’t say definitively, they’ll probably be just fine. While it’s not ideal, that’s not a giant swing in temperature. People intentionally do cooler water changes on things like Cory’s to try to trigger them to spawn. 
 

When it rains in nature, it’s essentially a cooler water change. If it was me, I’d let the heater take care of gradually bringing the temp back up to the desired range. 

[Flumpweesel]

My shrimp tank dropped to below 13C (55F ish) overnight this winter no issues I have thrown a heater in there since to keep things from getting crazy. They are breeding like crazy at the moment with tank temps about 19C (66F).

[Lennie]

Tbh, I always make around %20 water change with like max 15C tap water or probably even colder in a tank where I keep at 25C normally. I keep shrimp, lots of tropical fish and snails. But what I do is, I introduce the water to the tank very slowly. Might not be ideal, but it is followed by breeding actions, and I can’t see them being unhappy and breeding. I’ve never faced any issues myself in this way. But also I’ve never noticed the reactions you mentioned as well.

Potentially water parameters being changed instantly or introducing colder water fast might be the issue?  Is this the ratio you always make ur water changes? I’m thinking of different water parameters thanks to RO instead of temperature change, or temperature changing instantly

 

[mynameisnobody]

My shrimp are in a 40 gallon outdoor pond, year round. I do have 1 ACO heater in it, but it still has dropped into the 50’s. Nothing seemed to have been effected. I purchased my shrimp from LRB and on his site, it states that he has seen neo’s survive into the 90’s and down to freezing water. Obviously you don’t want to do this for long, but the point is, the shrimp will be ok. 

[nerdyaquarist]

Thanks everyone for your insight, it’s been a little while now and all my fish are fine but I did see a shrimp body the day after the water change. Unsure if it’s related. I think I learned my lesson now though, I’ll wait for spring to do 30% water changes. Thank you all!!

[Lennie]

On 2/10/2023 at 12:46 AM, nerdyaquarist said:

Thanks everyone for your insight, it’s been a little while now and all my fish are fine but I did see a shrimp body the day after the water change. Unsure if it’s related. I think I learned my lesson now though, I’ll wait for spring to do 30% water changes. Thank you all!!

If your water parameters got changed due to RO, they might be molting. Some may look dead when they have a struggle while molting, maybe due to low gh/low calcium and it may take hours sometimes. I would suggest leaving it in the tank and observe if it will be molting or not for some time. I've seen this happened in my tank before, and after a couple hours shrimp was no longer in that position. I dose equilibrium and keep a cuttlebone in the tank but I still saw it  three times  the last year. One time, the shrimp was dead for real tho.

Here is a video you may see below.