First things first:
1. Size of tank - 150l
2. Water parameters
a. Ammonia - 0
b. Nitrite - 0
c. Nitrate - 10
d. pH, KH and GH - 7.4 pH, ~8 KH, ~12 GH
e. Test kit - Testing Strips
3. Temperature - 25.5 C
4. FW (fresh water) or BW (brackish) - Fresh Water (Tropical)
5. How long the aquarium has been set up - ~ 1 month (Fishless cycled before this point)
6. What fish do you have? How many are in your tank? How big are they? How long have you had them?
In order they were put in:
- 1 x Bristlenose Plec
- 10 x Harlequin Rasbora (2 might be copper/glowlight rasboras)
- 1 x Clown Plec
- 5 x Diamond Tetra (present for ~3 Weeks)
- 10 x Cardinal Tetra (Present for 1.5 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)
- After noticing symptoms but failure to diagnose, the single infected rasbora (as far as I can see) was quarantined. However as I do not have a separate quarantine tank, it is instead in it's own floating bag in the aquarium (see pic below)
8. a. Any live plants? Fake plants? - Real plants only, present since cycling.
b. Sand, gravel, barebottom? - Mid sized gravel.
c. Rocks, woods, fancy decors? Any hollow decors? - Bogwood/driftwood (1 large, 2 small) plus 1 fake rock feature (see pic), all present since cycling
9. a. Filtration? - Aqua One Aquis 750
b. Heater? - Unknown, came with tank and specced correctly though.
10. a. Lighting schedule? What lights are used? - Standard tank lights, on for ~10-12 hours daily.
b. Any sunlight exposure? How long? - Minimal, if any.
11. a. Water change schedule? - 7-9 days (last change ~4 days ago)
b. Volume of water changed? - ~12-15%
c. Well water, tap water, RO water? - Tap water
d. Water conditioner used? - Aqua Care Water Conditioner plus Aqua Care Biological Supplement (similar to Stress-Zyme)
e. Frequency of gravel/sand (if any) vacuumed? - As much as possible during water change, approximately 20% each time.
12. Foods? - Flake foods
How often are they fed? - 1-2 times daily
13. a. Any abnormal signs/symptoms?
- 2 cysts or strange growths, rapid respiration, lethargy, rolling/flipping over, then righting self. Before quarantine, a couple of other rasboras appeared to nudge it while it was upside down.
b. Appearance of poop? - Unknown
c. Appearance of gills? - Normal I think.
14. a. Have you treated your fish ahead of diagnosis? - No, can't figure out what the problem is.
b. What meds were used? - None yet.
15. See attached pictures
Only noticed this afternoon, all appeared fine before then - at least for the rasboras. I've been keeping an eye on the Diamond Tetras and Cardinals over the last 24-48 hours as a couple of them appeared to develop a single white spot on their tail fin. White spot has disappeared today from all but one Diamond Tetra, but a single Rasbora suddenly developed the condition described above.
I have no idea what the issue is, or how to treat it, but my biggest concern is making sure the rest of the fish are safe. I'd really appreciate any swift help and advice, thanks everyone.
Also - unrelated but curious anyway - I have attached a picture of one of the Diamond Tetras. This one came with a missing eye (left side, can't see in picture), and has a significantly darker/bluer skin tone compared to the other Diamonds. He's been swimming around and feeding fine though with no signs of a problem, but is this normal?