Which sizes of Eheim jager trutemp should i get

I seem to be having trouble with fry now, with outside being cold, i had cory fry died the day after they hatched, and also pleco fry so I'm guessing it to be the cold weather, what size heaters should i get for these tanks:
7 gallons
12 gallons
30 gallons
40 gallons
50 gallons
100 gallons

I'm looking at the eheim jager trutemp, right now the temperature fluctuates between 75 to 79°F. November to Feb is our coldest month with February being colder, alot of people here get ick issues in February, last couple of years i lost all my rainbow fish, barbs, tetras and guppies to ick in February. Normally our temperature does be 80 to 83°

 

I don't see the need for heaters if the temps are between 75-79.

 

I don't see the need for heaters if the temps are between 75-79.

So the fry dying 1 day after hatch might be a different problem?

 

I think so. Unless the temp dropped rapidly after they were born.

Cold temps don't cause ick. Temps in the mid 70s are not stressful to the fish unless they prefer very cold water.

If you fill in the emergency template it would be helpful. It covers most questions people here will ask you when trying to help you figure this out.

 

I think so. Unless the temp dropped rapidly after they were born.

Cold temps don't cause ick. Temps in the mid 70s are not stressful to the fish unless they prefer very cold water.

If you fill in the emergency template it would be helpful. It covers most questions people here will ask you when trying to help you figure this out.

Why i said i feel it's the cold because on morning when i come outside an look at the tanks the glass does be foggy an cold,all now the water feel like chilled water

 

I think so. Unless the temp dropped rapidly after they were born.

Cold temps don't cause ick. Temps in the mid 70s are not stressful to the fish unless they prefer very cold water.

If you fill in the emergency template it would be helpful. It covers most questions people here will ask you when trying to help you figure this out.

I’ve alway heard cold temp is what starts ich. All fish have it but the immunity system keeps it from spreading. With a temp drop the fish are fighting the cold and the immunity system weakens give the ich its chance to spread. The answer to kill it was always raise the temp in the tank to 86 for 3 weeks. Now there are meds to kill it off. Also it’s mostly seen in the winter in pet stores. Where fish are delivered in unheated bags.

 

Certainly stress will invite infection. Maybe we need to define "cold"

In the OPs case, if 75-79F is "causing" ick, there have to be some other serious issues.

Why i said i feel it's the cold because on morning when i come outside an look at the tanks the glass does be foggy an cold,all now the water feel like chilled water

Looking at the tank and touching the water are unreliable methods. Use a thermometer.

 

I’ve alway heard cold temp is what starts ich. All fish have it but the immunity system keeps it from spreading. With a temp drop the fish are fighting the cold and the immunity system weakens give the ich its chance to spread. The answer to kill it was always raise the temp in the tank to 86 for 3 weeks. Now there are meds to kill it off. Also it’s mostly seen in the winter in pet stores. Where fish are delivered in unheated bags.

I was saying so to because i don't get ick unless it's February the coldest month here, and I'm not alone in this situation alottttt of people get ick in February here also, that's when most ick medication sells

Certainly stress will invite infection. Maybe we need to define "cold"

In the OPs case, if 75-79F is "causing" ick, there have to be some other serious issues.

Looking at the tank and touching the water are unreliable methods. Use a thermometer.

What thermometer do you use?

 

Any thermometer will work. None are 100% but they are close. Even the covid point and shoot thermometer work great. More money but not attached to one tank.