Temperature Fluctuations And Fry

[HeatherW]

I'm expecting Platy fry any day.

I plan to put them into a little cycled 2 gallon with a 7.5 watt heater and a small filter unit.
The heater does not have a thermostat built in, but merely raises the temp a few degrees.

My main tank (where they will be born) is kept at 78 degrees fahrenheit.
The fry tank is 76 in the evening and 74 in the morning as it is mildly affected by room fluctuations.
We are not about to run our heat in the whole house overnight.

My question is will fry withstand a daily fluctuation cycle such as this?
~~~(I know it isn't best, but could not find a small enough heater with a thermostat)
Also, how do I best climatize them from the main tank to the fry tank after birth?
~~~In a floating baggie like store bought fish?

They will be born in a Penn Plax Aqua nursery, a circulating breeding unit.
Mom in in there without the "V" insert. Babies get siphoned into another chamber.

A family friend just offered me her 40 gallon! I need to convince the household there is room.
Then the 20 gallon can be my fry tank, and I won't have to worry about this......
I think I caught the bug.......

Thanks, Heather

 

[Tolak]

I'm sure they will be fine. Fish tolerate daily temperature fluctuations in the wild.

Tolak

 

[Tokis-Phoenix]

Fry are far more sensitive to temperature fluctuations than their adult forms though, generally speaking, the smaller the fish the more sensitive it is to temperature as fish's body temp and metabolism are controlled by the temp of the water that surrounds them. Personally i would get a more powerful heater, i think(but im not totally sure) that its supposed to be 5watts to every gallon.
Also you have to understand that livebearer fry won't stay small for long and will quickly outgrow a 2gal depending on how many you have, i would definatly take up that 40gal and 20gal tanks offer B) !

 

[nmonks]

It depends what you're after. Low temperatures slow down metabolism, and therefore growth. Although fish grow constantly throughout their lives (unlike mammals) the rate at which they grow is defined within certain time periods, with maximal growth when they are very young. As they age, their growth rate slows down.

So, if you want your fry to turn into the biggest possible fish, then you want to keep them as warm as possible, constantly. If temperature fluctuates, they will still grow, but irregularly, and their maximum size may be less. As others have said, some variation in temperature is natural, and your fluctuations between ~23 to 24 C (compared with 25.5 C in the main tank) isn't going to make much difference. Moreover, some platies (variatus platies) arguably actually do better at slightly cooler than normal conditions.

(Obviously there are other factors, such as preferred temperature, involved, and coldwater fish won't do well if kept at tropical temperatures.)

Cheers,

Neale

 

[chrisquinn12]

dont worry about small temp fluxuations...

Nearly all heaters sold have what is called a hysteresis zone which simply means the temp will drop 0.5 - 1.5 deg before the heater will turn on again. Otherwise the heater will need to turn on and off very quickly and often. Not good..for the heater...

So temp fluxuations 0.5 - 1-5 deg will happen for sure.

I'm an electrician by the way...

 

[cassie2]

I went thru the exact same thing with my 5 year old daughter's platies - we had fry and she wanted me to try to save them. We first had a breeder net in the big tank - hanging off the side in the tank - then I chased the fry around and caught them (took a while to get good at that, but now I can catch fry pretty quick!!) The did well in the breeder net - I added a plant cutting for them to hide in as I didn't like the plastic plants in the net. Then I decided that they need their own home. So we bought the 2 gallon tank.

We have the 2 gallon plastic tank, the mini filter (spongy stuff and carbon only, no bio part), and the 7.5 watt heater that you have to plug in which does NOT have a thermostat so if you leave it in, it'll boil the fish. I used gravel from the big tank so as to move over some bacteria, plus plants (cuttings) from the big tank, and I also have a small bubbler going, plus the mini filter. I also got a little thermometer. I also have snails in the big tank, so I made sure that a couple came over to help eat the overfeeding, (the snails are now breeding, but thats another story). I try to change the water a couple of times a week (25%) to help keep the chem. ok, but otherwise the tank has worked very very well.

When I first moved them - I cleaned and did a water change in the big tank. Then I set up the 2 gal. tank using the gravel from the big tank AND I put in water from the 10 gallon tank - so the temp and conditions were right out of the big tank. Then I put in the fry, and well, then the temp started to fluctuate so I tried to fix that after the fish were in.

The tank really lost about 10 degrees overnight and warmed back up only when we turned on the table lamp over the tank. I knew the fry would not like that much. Then with the 7.5 watt heater, I noticed the temp rose steadily then kept going over 80 degrees, so I was constantly checking temp, and plugging and unplugging the heater, plus overnite was tough - let it cool or boil?

SOLUTION: I got a lamp timer - a 24 hour one - where you pull up the tabs for on and push down for off (or the other way ... I forget), but anyways, in a 24 hour period I have the timer turning "on" for an hour then "off" for an hour. I plugged the 7.5 watt heater into the timer and it works PERFECTLY - 78-80 degrees all the time.

Give it a try - our fry are 3 months old now and the biggest have been released into the main 10 gallon tank and are doing well.

Good luck with the fry!!