Fish Temperatures

[Pawnic]

Hi Everyone,

 

I live in Austin, TX, and my tank ranges from 74degrees in the morning to 91degrees in mid-afternoon. I don't see fish adapting well to this range at all. It is a glass tank that sits above ground, and it is in shade all day. I plan on putting some shade netting around the tank anyways, to hopefully cool it down a bit more, but I don't think it will make much difference. Does anyone have any suggestions?

[Jonathan Hall]

Didn't ready everyone's post, just the first 10 or so, so sorry if this is a repeat.

I recommend you save a few soda bottles and freeze water in them every night.

In the late morning place them in the tanks.

Use more or less depending on how it works out.

or you can get a chiller.

[Tradewind]

This is a pretty old thread and I thought perhaps some of those that posted may have come up with a solution.  I saw at least two who posted that are from Texas as I.  I don't know that reflective barriers or shade netting (I have a 50% screen on mine) will actually make any difference to the water temperature.  I say that because my water is basically the same as the ambient temperature.  It is much like trying to modify the temperature of a pot roast in the oven.  It is going to be eventually rising to the temperature that surrounds it.  The only thing I know to do is to inject a source of cold to the water to offset the ambient temperature.  That is expensive and most DIY projects offer dismal results.  That being said, a local bait shop here has about a 100 aquarium with shiners.  He has an refrigeration unit with hose wrapped around the expansion coil and he keeps his tank at 65 degs.  But it is a closed loop system and the water is going nowhere else.  I believe that the grow beds and sumps, DWCs, or NFTs would pick up more heat than one can offset.  The media grow beds will probably grab the most heat.   I am not sure there is a solution other than moving.  I guess the only option we have is to try and select fish that will tolerate the heat and keep dissolved oxygen as high as we can get it.  Hot water does not hold a great deal of oxygen and thus even air stones will have only a marginal effect.  It can be done, but it will take a chiller with a very large btu capacity to bring the temp down considerably.

I will certainly continue to study the subject and perhaps I will stumble upon something that will help. I am currently experimenting with bring water down to a very cold temperature and submerge about 100 ft of small diameter irrigation tubing in the cold water.  Plastic does a terrible job of transferring heat, but perhaps if I get the tubing cold enough to will have an effect.  The only other options are expensive, that is titanium or upper end stainless steel heat exchangers. Will it offset all the other things I mentioned?  Probably not, but if I can drop it 10 degrees or so, that would help a great deal.

[George]

use fish that can tolerate the temperature swings

plants shading the grow beds will help

[TCLynx]

If your day/night temp swings are large enough, as in if the night time temperature drops considerably compared to your day time high, AND you have a large volume of water (avoid NFT) then the thermal mass of the water will resist the swing so the day time high of your water will never be quite as high as the air temp and the night time low of the water will never be quite a cool as your air temp.

Now if it doesn't cool off much at night, your water will be warm.

System position and shading can have a huge effect.  I have several systems and the systems with the towers (essentially vertical modified NFT pipes) has the greatest temperature swings because the towers do let the water heat up quite a bit.  The media beds will heat up but they come with a certain amount of their own thermal mass so the heating/chilling is delayed a bit and if the system has a large water volume it will heat up slowly.

A system out in full 100% sun all day long will heat up more than a system that gets afternoon shade or has aluminet shade cloth over it.

but if your ambient in the shade air temp is 100 F and it's too humid for the air to cool off much at night, you better have a warm/hot water tolerant fish and keep the water well aerated.  reduce feed as the water temp gets above 86 F

[Tradewind]

Yep, that is pretty much the conclusion I have come to.  I was somewhat mislead by the so called local experts as to what fish would tolerate or would not tolerate.  I have already debunked one of their myths as you read on another post back to you.

TCLynx said:

but if your ambient in the shade air temp is 100 F and it's too humid for the air to cool off much at night, you better have a warm/hot water tolerant fish and keep the water well aerated.  reduce feed as the water temp gets above 86 F

[TCLynx]

Yea, stocking density, aeration, dissolved oxygen and temperature as well as feeding can get into a very important interplay when the water temperatures get hot.

[sticky]

TC,

I am having problems with random fish death and i am trying to determine if its under feeding, temperature or something along the lines of DO caused by the summer heat ( i live just to the north of you in leesburg). so, can you recommend a DO tester and maybe a automatic feeder. I work away from home so i need to be able to set up something that keeps my fish feed while i'm gone. thnks

TCLynx said:

Yea, stocking density, aeration, dissolved oxygen and temperature as well as feeding can get into a very important interplay when the water temperatures get hot.

[Alex Veidel]

Have you tested your pH, ammonia, nitrite, and nitrate levels?

sticky said:

TC,

I am having problems with random fish death and i am trying to determine if its under feeding, temperature or something along the lines of DO caused by the summer heat ( i live just to the north of you in leesburg). so, can you recommend a DO tester and maybe a automatic feeder. I work away from home so i need to be able to set up something that keeps my fish feed while i'm gone. thnks

TCLynx said:

Yea, stocking density, aeration, dissolved oxygen and temperature as well as feeding can get into a very important interplay when the water temperatures get hot.

[sticky]

oh yea, all that is good. the only thing that has changed in the last couple of weeks is the temperature and how often i feed the fish. When i am home i feed them twice a day and everything seems fine, but when i am gone they may only get feed 2-3 times a week and that is when i start getting dead fish. one here, two there; i really think they are being underfed which is why i am looking for an automatic fish feeder, however considering the summer heat and the fact that my whole system gets 100% sunlight (only partial shade late in the evening) i didn't want to leave other possibilities on the table.

[Tradewind]

I do not know if this relates to you situation, but I lose a fish now and again.  Mostly the smaller ones.  But I think I know what is going on.  I have two species of fish one is goldfish and the other is a bait fish called "Shiners".  In the beginning the Shiners were dying by the numbers, but it was what I expected due to the difference in the environment from which they came.  From 65 degs to 97 degs.  And my system had not quite settled out at that time.  But since, the remaining Shiners are very alive and very aggressive.  When I feed the fish, the goldfish do what they do and the Shiners hit the surface like a large mouth bass jumping on a top water bait.  They also bang the goldfish around pretty good.  I believe the occasional floater is a Shiner victim.  But their day is coming.  This fall I will be adding Hybrid Striped Bass or Blue Gill or maybe some of each and as soon as they are large enough the tables may be turned.  I have read that Shiners could grow to the size of pike in the right environment.  I have witnessed considerable growth of them in my little tank.  Maybe the victor is yet to be determined.

Alex Veidel said:

Have you tested your pH, ammonia, nitrite, and nitrate levels?

sticky said:

TC,

I am having problems with random fish death and i am trying to determine if its under feeding, temperature or something along the lines of DO caused by the summer heat ( i live just to the north of you in leesburg). so, can you recommend a DO tester and maybe a automatic feeder. I work away from home so i need to be able to set up something that keeps my fish feed while i'm gone. thnks

TCLynx said:

Yea, stocking density, aeration, dissolved oxygen and temperature as well as feeding can get into a very important interplay when the water temperatures get hot.

[TCLynx]

Hi, sorry I haven't been on much lately.

What kind of fish sticky?  How Big?

Automatic feeders are dangerous and often problematic while also tending to cost quite a bit so I advise extreme caution.  over feeding is generally far more dangerous to fish than under feeding.

What size system?  How much would you be feeding at a normal feed?  Aquatic Eco systems has the Koi Chef fish feeders that might be appropriate depending on the system size.  I have Auto Pet Feeders but they are pretty costly and have to be kept out of the weather though they are pretty adjustable.  Unfortunately I don't think any of the feeders really keep the feed sealed up well enough to keep much food from being exposed to our humid air and bugs.  When you are away working, how long are you away at a time?  Is it that you are just working long hours so can't be home during daylight to feed the fish?  Or are you away for a week at a time?  Who checks on your system while you are away?

[sticky]

Here is my set up as it stands right now. The IBC container in the foreground is a 330 gal tank that is kept at a constant 205-210 gals, this is where i keep my fist. The tank in the back is a 270 gal tank but won't get above 110 gals, this is where i keep my pump. My system runs about 300 gals total, the tubes in the back are not being used right now, they are for DWC, but i'm not running them. At one point i was pushing 90 fish but i have lost a lot recently, so i would estimate somewhere around 70. They are a combination of tilapia and feeder goldfish from the local pet store. I purchased the goldfish to test and establish my system and once everything was good i added the tilapia. I was feeding them twice a day very consistently, every now and then i would miss a feeding, but they seemed fine and where growing well. The tilapia range from 1-2 inches in length and the goldfish are probably 1 inch or less. I have been using goldfish flake food from the petstore, i have tried koi pellets but the fish don't seem to want to eat them.

everything was fine till about a month ago and then i started working away from home for about a week at a time. My wife would feed them 2 maybe 3 times while i was gone. i wasn't too worried about it because i had gone a whole week without feeding my fish in the past and they seemed to do just fine. but now i am losing 4-5 fish a week, almost exclusively tilapia, and i am just not sure what it could be. the only thing that has changed in the last month is my frequency of feeding them and the temperature. The whole system is outside and gets 100% sunlight all day long. The tanks are covered to prevent algae blooms, had that problem already, and i spray painted them first black to block any sunlight from getting in and then white to keep them from getting too hot. I'm just not sure where to go at this point, i can't keep my fish from dying and it is getting quite frustrating.

thanks for your help.