Goldfish fry ill ness?

Hello, this is my first time on forum. I hatched goldfish eggs from my pond early September. There were approx. 100 fry, but one grew like a mutation and ate most of them overnight. I separated larger and tiny fry into two tanks. Many of the small fry still look like newborns. The tanks have cycled. The test strips are fine and no nitrates or ammonia. I have well water, so no chlorine. Have heater at 75 ish and use a round sponge filter with internal air stone. They are getting a well rounded diet ,( see picture), and I clean gravel once a week. Only do water change if water is getting too cloudy, or there is an increase in nitrates, but it's been good for since I got the two tanks. The issue I am writing about is that a few of the 'larger' fry have see through bodies with red streaks and very large black eyes. Could this be a result of previous Nitrate damage or bacterial infection? They seem to be active and eating. If you know the diagnosis, Is there anything I can treat them with now? Thank you, Bettachon

If we saw a photo of the other parent fish, that would be great. Otherwise I am going to assume everything is fine here, because new fish fry like goldfish don't develop colors until their a little older OR you could just have white colored goldfish.

The black eyes are most likely just their normal eye color (just black) and their "red spot" on their gill plate could just be their gills which are red, and their gill plates could be semi-transparent

This website: Eggs & Fry seem to have goldfish fry that have similar color schemes to you.

HOWEVER: some parameters like PH, ammonia, nitrates, etc. would also be nice and help (incase there actually is a problem.)

Oh, and congrates on the new children lol

Hello again,
Thank you for getting back to me. I am glad to know the 'see through' fish are normal. I am enclosing pics of the babys and the adult fish. There are two tanks. The10 gal. is brand new for the 'larger' fish- ha ha. That's why it's still cloudy. There are about nine in there. The largest one is the killer of half the population in one night. The 5 gal tank has the littler ones. You can see the smallest one is at the bottom of the sponge filter. He looks the size of a newborn. Most of the other 10 are also pretty small. The water quality reads within normal parameters, except sometimes the nitrite and nitrate are a pale pink. I do small water changes and add a nitrate remover. Ammonia is neg. I have an electric gravel vac, that is gentle and seems to get a lot of detrius out. after working in the tank, I add a drop of Stree Guard. I do The temp is 74 ish. The sponge filter has an air stone in the plastic straw and is gentle and quiet. Their diet is a variety of protein, vegetable, brine shrimp. I cannot fathom why they are not growing at at least a semi normal rate. They appeared the last week of August or the first week of Sept . I am adding Malaysian snails very soon. one month quarantine. The other pics are of the pond fish. The 2 white ones are male and female. They were the predominant mating pair. There are 4 regular goldfish, five multi colored Shebunkin including a black and red one. THEN there is the big Blue one. He used to be a Shebunkin for a few years. He was small for years and this spring grew as large as the white ones. Then SURPRISE, at the beginning of fall, I noticed how he had a growth spurt. That's when I saw the barbs, and realized I'd gotten a Koy baby mixed in with my shebunkins. Knew he was special all along. Whenever I emptied the pond to clean and netted the other fish, he would jump out of the water and over my shoulder to land behind me. So the gold and shebunkins, (and of course white), could be contributers, but not Blue due to his Breed. PLEASE, I don't want to be a GM forever. I was hoping to place them in a mini pond with a heater when they are big enough. I hope you have advice on how to get them to the normal percentile of growth. Thanks again, Bettachon

Looking at the adults, the fry definitely look like them. I'm not a goldfish breeder so take my advice with a couple grains of salt.

Growth isn't just affected by food, but the water volume can also be affecting the growth rate. I'm sure someone else can help you grow them out though since I don't have experience growing goldfish.