Fish have white spot, should I use Methylene blue?

I notice all my fish in my main tank have white spot on their fin. Should i just treat the whole tank with methylene blue? I don't have heater so i can't raise the temp in my tank unless there is other method to do so.

If so, should i remove the live plant, shrimps and sponge filter?

I wonder if removing sponge filter will kill the shrimps

 

Please can you fill the template in so that everyone can see your tank water quality and its residents/history, thank you

Aquatic Emergency Template | Freshwater Fish Disease and Fish Health Forum | 376562

 

Tank
What is the water volume of the tank?
Around 38-40litres
How long has the tank been running?
3week
Does it have a filter?
Sponge filter
Does it have a heater?
No
What is the water temperature?
23.8 Celsius
What is the entire stocking of this tank? (Please list all fish and inverts.)
-9 guppies, 10 cherry shrimps

Maintenance
How often do you change the water?
Weekly
How much of the water do you change?
25%
What do you use to treat your water?
Anti chlorine
Do you vacuum the substrate or just the water?
Both

*Parameters - Very Important
Did you cycle your tank before adding fish?
Yes
What do you use to test the water?
Api test kit
What are your parameters? We need to know the exact numbers, not just “fine” or “safe”.
Ammonia:0
Nitrite:0
Nitrate:6
pH:7.2

Feeding
How often do you feed your fish?
Two to once a day
How much do you feed your fish?
Small amount
What brand of food do you feed your fish?
Aquadene fish flakes
Do you feed frozen or freeze-dried foods?
No

Illness & Symptoms
How long have you had this fish?
2 week
How long ago did you first notice these symptoms?
Today
In a few words, can you explain the symptoms?
White spot on fin
Have you started any treatment for the illness?
Havent
Was your fish physically ill or injured upon purchase?
No
How has its behavior and appearance changed, if at all?
No changes

 

One thing jumps out at me at least....

You say the aquarium has been running for 3 weeks and the livestock introduced 2 weeks ago, that isn't fully cycled before you added the stock. Fishless cycle takes an average 4 to 6 weeks (with fish add on average 4 weeks on top of that)

A mature cycled aquarium is essential for shrimp too.

There is a heat discrepency on the livestock which is not going to help here. Guppies are temperate so they can be happy in unheated water but are not so keen or healthy in heated water, which your shrimp would be more comfortable with.

Shrimp average 25 to 27 and guppy average 22 to 28....so your water is a little on the cool side for the shrimp really.

Can you take a few photo's of the spots please

 

One thing jumps out at me at least....

You say the aquarium has been running for 3 weeks and the livestock introduced 2 weeks ago, that isn't fully cycled before you added the stock. Fishless cycle takes an average 4 to 6 weeks (with fish add on average 4 weeks on top of that)

A mature cycled aquarium is essential for shrimp too.

There is a heat discrepency on the livestock which is not going to help here. Guppies are temperate so they can be happy in unheated water but are not so keen or healthy in heated water, which your shrimp would be more comfortable with.

Shrimp average 25 to 27 and guppy average 22 to 28....so your water is a little on the cool side for the shrimp really.

Can you take a few photo's of the spots please

I see, i have to correct myself. I add the water in my aquarium on February. I thought running a tank meant with filter+fish and plant, English isn't my main language, my bad. 3 week ago i added the shrimps after a month of exposure of my aquarium. And then after a week i add the guppies in.

Here is the photo on one of my guppies that had white spot on fin.
After viewing many ick treatment sources, i think i will just buy a heater as i seen it's the most common and best way to kill ick in the entire tank.