Help! My platys are paralyzed and sink!

[Shellbug]

So I recently got 12 fry from a friend and they are about 2 months old, varying in size. I have 4 of the tiniest ones in a 5 gallon, the rest in a 20 gallon. About 3 days ago I noticed a few were missing and couldn't see them. I thought they were just hiding but then today I noticed some just were gone, no bodies, and I gently lifted some decor and they were sitting on the base of the decor, not able to use their tails.
They are paralyzed after their front fins. I'm testing their water at a petstore tomorrow (I'm still a newbie, don't have everything). But I only found 5 left out of the 9 fry.
They are all less than an inch still, very small, so I know it's a touch crowded but once I can sex them I'll get another tank. I recently got new decor from amazon 4-5 days ago. I rinsed it in hot water before putting it in. Idk what do do!
They are currently in a gallon bucket with new fresh water and some crushed peas, in case it's some weird swimmers bladder thing.
HELP!
(The 3 in the 5 gal are completely healthy and energetic)

 

[Colin_T]

Hi and welcome to the forum

The best thing to do for any fish that is acting unusual, is a 75% water change and gravel clean the substrate each day for a week. Make sure any new water is free of chlorine/ chloramine before it is added to the tank.

Clean the filter if it hasn't been done in the last 2 weeks.

Take pictures of the fish and maybe a short 20 second video and post them on here so were can see how the fish are moving (or not moving).

There's more info on fish health at the following link if you want to read it. It's pretty long and boring but worth a read when you have a spare moment.
http://www.fishforums.net/threads/what-to-do-if-your-fish-gets-sick.450268/

 

[Shellbug]

Thank you, I swapped out about 60% of the water before you sent this reply and "quarantined" the remaining fry to a container with new water (75% new) and waited. I wanted my water to filter and I'm testing it today in a few hours. Theres only 2 left but their condition seems the same. Im unsure if I should put them back into something so big if they can't come to the top for food, but then again. they aren't eating much now

 

[Shellbug]

Thank you, I swapped out about 60% of the water before you sent this reply and "quarantined" the remaining fry to a container with new water (75% new) and waited. I wanted my water to filter and I'm testing it today in a few hours. Theres only 2 left but their condition seems the same. Im unsure if I should put them back into something so big if they can't come to the top for food, but then again. they aren't eating much now

 

[Shellbug]

I'm not able to upload a clip, I can't get a file small enough, but basically their usually fanned tails are completely closed and they can only move their fins

 

[Colin_T]

Clamped fins/ tails are normally caused by poor water quality, protozoan or bacterial infections. Poor water quality and protozoan infections being the most common cause and big daily water changes will usually fix it.

You need to get the food and crushed peas out of the tank because they will create huge amounts of ammonia that will kill fish.

 

[Shellbug]

That pic is right after I fed them, I removed what I could about 15 minutes after feeding them. I went to the pet store and they said the nitrites and nitrates were really off. I'm not sure how it happened, but the ammonia was completely normal. So I'm going to slowly introduce water from the 5 gal into their temporary home and then put them in the 5 gal until the 20 gal is ready again. The petstore employee recommended Prime and about a 50% water change and then let it run for about 3 days. The 2 look a little better, so my fingers are crossed!

 

[Colin_T]

While you wait for the big tank, do a big (75%) water change every day for a week and on any day you have an ammonia or nitrite reading above 0ppm.

When you feed flake food crumble it up so the fish can eat the smaller pieces and you will have less wastage from food sinking to the bottom. Same with the peas, make sure the food is small enough for the fish to eat.

Remove uneaten food within a couple of minutes of feeding. The fish won't starve and if food is left in the tank for 15 minutes or more it will produce ammonia readings that can make the problem worse.

Newly hatched brineshrimp is a good food for baby livebearers. You can buy dry brineshrimp eggs from most pet shops and hatch them in salt water, then use an eye dropper to suck the baby brineshrimp out and feed them to the fish. There is more info at the following link on hatching brineshrimp eggs.
http://www.fishforums.net/threads/back-to-basics-when-breeding-fish.448304/

 

[Jeremy180]

The fact that your pet store told you that the ammonia was "normal" and the nitrites and nitrates are "off" without giving actual numbers raises a red flag for me.
Agree with Colin on the frequent water changes and feeding sparingly.
The majority of fish have tiny stomachs compared to mammals.

 

[Colin_T]

The majority of fish have tiny stomachs compared to mammals.

not my fish
I had Galaxias, which can expand their stomach so it runs virtually the entire length of their intestine. This is an adaptation to living with unreliable food sources whereby the fish might not get food for a month or more and then get lots of food. They can basically eat and eat and eat and fill their entire digestive tract with food. They are long skinny fish too so it looks weird when they do it.

 

[Shellbug]

The fact that your pet store told you that the ammonia was "normal" and the nitrites and nitrates are "off" without giving actual numbers raises a red flag for me.
Agree with Colin on the frequent water changes and feeding sparingly.
The majority of fish have tiny stomachs compared to mammals.

I don't remember the numbers (I have a horrible memory) but one was really dark blue and the other was dark magenta. I'm buying a testing kit soon of my own

 

[Colin_T]

If there is a possibility the water is not 100% perfect, do a big water change and gravel clean the substrate each day until you get a test kit or have the water tested.

 

[Shellbug]

If there is a possibility the water is not 100% perfect, do a big water change and gravel clean the substrate each day until you get a test kit or have the water tested.

I will, thank you. The remaining platy, only one survived, is doing better. He is still on his own in a dish I aerate a few times a day and have been slowly introducing the 5 gal water to it. He can't use his tail yet, but I everytime I check him his from fins are working away. He reacts everytime I add water and his energy is high. I'm getting a water testing kit tomorrow and the 20 gal tanks has been 60% change so far, cycling for about 4 days now, gravel cleaned, and took all the decor out and gave them another rinse in really hot water.
Thank you for the advice! I'm still not entirely sure what happened but hopefully I can save at least one of the fry. He's going to need the perfect name after this whole ordeal

 

[Colin_T]

There is no need to wash decorations in hot water. If they are dirty you can hose them off or rinse them under cold tap water. The only reason you use hot water is to sterilise/ disinfect items and the temperature has to be about 60C for a few minutes to kill things.

 

[Cichlid4life]

that is lethargic behavior, not fish getting paralyzed.