First off is my fancy goldfish tank overcrowded? I have two fancy goldfish and one dojo loach. I can give the loach a new home easily if my tank is overcrowded. My tank is 29 gallons. I love my goldfish so much, I think they may be sick. They are eating normally and active but one has these tiny white dots on his fins. Not his body just fins. The other is starting to get these dots on his fins as well. Please tell me what this illness is and how I need to go about treating it.
The picture is a week old but those are my babies.

Cute fish. Tiny white dots usually mean ich. The good news is that ich is very treatable. Your lfs should carry medication that you can just add to the tank, usually for several days in a row. If you are filtering with carbon, make sure you remove that before adding the medication.

In my opinion, your tank is over crowded, or soon will be when the fish reach adult size. i would rehome the dojo loach.

Ich is an odd parasite, in my experiances i have had ich clear up is as little as two days, and as long as two weeks, it depends on how quickly you catch it. One thing i do to help with ich is add a little aquarium salt, and maybe turn up the heater a little, luckily ich is pretty commonplace, and therefore easiy to cure.

"First off is my fancy goldfish tank overcrowded?"
The answer to this question is found by testing the water. In my experience, ich is present in nearly all tanks but only presents symptoms when the fish's immune system is compromised by foul water. Here, I will make a dichotomous key for you to follow. Test the water's concentration of ammonia, nitrite, and nitrate and then follow this question chain:

1. Is your ammonia at 0 ppm?
Yes: Good, that's what it should be. So far so good. Continue to question 2.
No: That is not good. Your fish tank is not performing a complete nitrogen cycle, and the nitrogen from fish waste is getting stuck during the conversion step from ammonia to nitrite. Either increase the amount of beneficial bacteria or decrease the amount of waste. To increase the amount of beneficial bacteria, increase the number of homes for them. Add a synthetic sea sponge to your waterfall filter. Upgrade from a waterfall filter to a fluidized bed filter. Add live plants. All or any of these things would help. Continue to question 2.

2. Is nitrite at 0 ppm?
Yes: Good, that's what it should be at, for the tank to be completely cycled. Continue to question 3.
No: That's a problem. The nitrogen cycle is getting stuck in the conversion step from nitrite to nitrate. Either increase the amount of beneficial bacteria or decrease the amount of waste. To increase the amount of beneficial bacteria, increase the number of homes for them. Add a synthetic sea sponge to your waterfall filter. Upgrade from a waterfall filter to a fluidized bed filter. Add live plants. All or any of these things would help. Continue to question 3.

3. Is the nitrate below 30 ppm?
Yes: Good, that's what it should be. Your water is clean and your fish should be healthy/recover from their illness. Your tank is not overstocked and your present schedule of water changes is keeping up with their waste production.
No: That's not good, the fish's waste is accumulating faster than it is being removed. Continue on to question 4.

4. Do you have live plants?
Yes: Good. They're helping you by absorbing ammonium and nitrate. But since you only would have gotten to this question if your nitrate was above 30 ppm, it means your plants aren't keeping up with the waste produced by your fish. Start doing more frequent water changes, for example increasing from 10% once a week to 25% once a week. A second example would be to increase from a 25% water change every other week to a 25% water change every week.
No: You might want to consider adding a live plant to eat your fish's waste. Also consider doing more frequent water changes. One example of increasing water changes is increasing from 10% once a week to 25% once a week. A second example would be to increase from a 25% water change every other week to a 25% water change every week.

Conclusion:
Once you have clean water again, with ammonia at 0 ppm, nitrite at 0 ppm, and nitrate less than 30 ppm, the fish should recover from their ich. Yes, a little bit of medication and/or salt will help, but the major thing here is the clean water. They will probably recover on their own once the water is cleaned. They will probably not be able to recover even with medication and/or salt if the water has too many nitrogenous compounds. Good luck. You care enough to ask this question, so I have a feeling you are going to take good care of your fish and that they will be fine :)

When i had to treat my tank for ich, i suspect it was introduced by a batch of new fish i added to my tank. They had it the worst, and i think it took a couple weeks to clear up, in fact, i might have even treated the tank twice. But the ones who didn't have it very bad to begin with cleared up within a couple of days. But i didn't lose a single fish, so i wouldn't worry too much.

I disagree with one point okiimiru, and that is that i think you can have an over crowded tank and still keep your ammonia, nitrite and nitrates at acceptable levels. I think that testing for ammonia, nitrate and nitrite is only one indicator of fish happiness and health. One very IMPORTANT indicator, but i think there are other things to take into consideration.

i would use aquarium salt and turn the heater up then treat the tank with the proper dosage turning up the heater helps with the reproduction cycle of ich they are only vonerable for three days so treat it steady for two weeks with the heater temp up also use aquarium salt more often other may disagree but i think it works