when cichla are very young, they are very delicate. the best temp for them is 86 degrees F. if you can, keep them in the smaller tank till the spring, it'll be easier to keep warm. add an air stone, 50% water changes each week are great, but should not be done all at once, spread it out, do 25% twice a week or even 3 times a week.
and the sooner you get them on killed food and pellets (if you choose) the better. at 3" it is very easy to switch them to frozen bloodworms, mysis shrimp and frozen krill. create a current in your tank with a powerhead or the filter outlet. thaw the food in a glass of tank water. then release the food in the stream of the powerhead. the little cichla will give chase and eat em all.
quit feeding goldfish now.. get them on the frozen food. do the same thing with pellets, sooner rather than later. i don't like the idea of fish kibble, and i resisted it for many years. but i found that i just couldn't keep up and feed cichla the volumn of food that they need without them.