1. Size of tank? 29 gallon
2. Water parameters
a. Ammonia? 0 ppm
b. Nitrite? 0 ppm
c. Nitrate? somewhere around 2 ppm
d. pH, KH and GH? around 8, soft water
e. Test kit? API Master liquid test kit (freshwater)
3. Temperature? around 24 C
4. FW (fresh water) or BW (brackish)? FW
5. How long the aquarium has been set up? a bit more than 2 months
6. What fish do you have? How many are in your tank? How big are they? How long have you had them? Cherry Barbs - 7 - biggest around 2 inches, others slightly smaller - around a month and a half; Harlequin Rasbora - 4 (used to be 7, but three have died) - around an inch - 2 and a half weeks
7. Were the fish placed under quarantine period (minus the first batch from the point wherein the tank is ready to accommodate the inhabitants)? no
8. a. Any live plants? Fake plants? floating water sprite, pygmy chain sword, Brazilian pennywort
b. Sand, gravel, barebottom? sand
c. Rocks, woods, fancy decors? Any hollow decors? two hollow plastic log decorations
9. a. Filtration? Penguin 200
b. Heater? 150 watt submersible
10. a. Lighting schedule? What lights are used? on at 11 AM, off at around 7 PM (not on a timer, latly it's been ore like 8 PM going off)
b. Any sunlight exposure? How long? no
11. a. Water change schedule? weekly
b. Volume of water changed? 33%
c. Well water, tap water, RO water? tap
d. Water conditioner used? Prime
e. Frequency of gravel/sand (if any) vacuumed? something like once a month
12. Foods? Omega one shrimp pellets and flakes
How often are they fed? twice a day
13. a. Any abnormal signs/symptoms? one fish has a white fin, and it's always sticking out, another one has some white fuzzy looking things on is body near his gills
b. Appearance of poop? haven't seen any (though haven't been looking for it)
c. Appearance of gills? one is normal, one has white fuzzy stuff around it, as mentioned before
14. a. Have you treated your fish ahead of diagnosis? no
b. What meds were used?
15. Insert photos of fish in question and full tank shot if necessary.

It's impossible to get clear pictures, they move so fast! But I hope you can get an idea of what I mean.
Also, on died of what looked like big white Tumors, and two died of nothing, as far as I could see. One died, didn't know what of, then a week passed and I though I was in the clear, then another died of "nothing" and one had the big white tumors, it survived through the day, and had died during the night.
I don't have a quarantine, not do I have the means to get one, if that makes any difference.
PLEASE help me try and cure my fish!