goldfish boo-boo?

my mom has 2 goldfish and i think they have ammonia burns. they have red marks on them since she did a water change yesterday but the marks didn't appear until after the water change. she is insisting it's from the clean declorinated water she added because you aren't supposed to clean the water. i am waiting for her to email me some pics. my daughter is very upset(she lives with them half the time) and she called me saying Gramma made her fish bleed. they are in a ten g that i finally got them to take. they were in a 2.5g until a month ago and it was really hard to talk them into upgrading. i tried to give them either a 30 or 20 but they said it was too big because the pet store lady told them they could keep them in 1g each. grr..... anyways, i'll post pics in a minute hopefully. is it possible for amonia burns to appear after a large water change?

she said she is sure she declorinated the water. she changes half the water weekly but only does a gravel vac every other week. i know this isn't enough but i can't win this argument. i had to be sneaky giving the ten g to my daughter and then saying 'well i already gave it to her, so i'm not taking it away now'. they don't measure their water parameters. the fish are about 2" long i think.

thanks for the quick reply, btw. still waiting for pics

i know. i was happy when my daughter told me she got a fish of her own but my mom doesn't seem to be very responsible with it. i think i can convince her to take a bigger tank by the end of summer. she's had them since november when the pet store was giving away free goldfish. they also sold her a $60 2.5g tank so not that free, right? i'm not sure what to tell her other than what i have. i think they are a comet and a common. they look the same but one has long fins and one has short fins. i don't know much about goldfish other than they are messy and they are supposed to grow fast. i had five before but they grew from 1 to 5 inches in a couple months and i had to give them to someone with a pond. so can you help me figure out what i should say that will help her see she's not taking care of them right? i have a 30g with filter and heater i have put away for her when she comes to her senses.

my mom said what am i supposed to do?

well, i have made some progress with her. it is slow coming though. she's going to do two 50% water changes weekly from now on. i feel bad for the fish. it's fins are clamped but still swimming and eating. i'd like to take them but i don't know where to put them. i will keep at her. I asked if she'd like to trade me for some white clouds or guppies. i might be able to talk my daughter into it

thanks for all the replies lupin. does it look like an amonia burn to you? (or anyone else) i'd like to try to save this fish(his name is rainbow). my daughter is in love with it. if they get upgraded and don't get killed i will set up another indoor pond for them. i have a 150g indoor pond already but if i put them in there they will just become food.