Greetings, all. I set up a new 29 gal tank 3 weeks ago populated with live plants. During initial setup of the tank, I added 2 bulbs that were mostly buried in my apparently plant-friendly substrate, along with some pregrown ferns, etc. Within 3 days, both bulbs had grown a dome of smoky, clear halo of some kind of substance (algae perhaps, but none like I've seen before), almost like clear aerogel around them, probably 1/2" thick each. Not knowing if it was a natural development of the bulbs, I let it be.

I added 4 glofish and 2 dalmation mollys a few days later. Within 3 days, all but 1 of the glofish had died, and the mollys developed a halo of the mystery gel around their heads, something I've not had experience with before. One became disoriented and died almost immediately after the aerogel-like stuff appeared, and the other lasted another two days but the back of its head lost scales and became red and extremely disgusting. I noticed that if there was a piece of food left after feeding, the next day it developed a gel halo. Not knowing what to do, I ditched the bulbs, scooped out the gel-infected material, did a 1/3 tank water change, and just let the tank sit with my one surviving glofish for two weeks to see what happened. No more gel grew, and the water always stayed crystal.

Thinking the tank was safe, yesterday I added 5 neon tetras and an angel. Everything looks good except a single pellet of food from last night's feeding is floating around in the tank and grew the halo.

Does anyone know what my tank's problem is and how to solve it? I'm stumped.

Thanks in advance,

Jared

Pertinent stats for my tank:
29 gal tank
Aqua-Tech 20-40 filter
API Stress Coat + conditioner
API Stress Zyme + biofilter booster
API Leaf Zone plant food
pH is currently high at 7.6 but I'm bringing it down with Seachem Neutral Regulator
Aqueon Tropical Flakes for the tetras
Tetra Tropical Granules for the angel.

They're rotting. I don't think your filter is running correctly, or it's not strong enough, OR your water is contaminated/dirty.

I agree, it's a fungus. I bought some of those bulbs too and the ones that started rotting I took out. Right now your water is full of spores and your fish got infected. Cut back on the plant food and feeding, and don't replace the fish for a week or two, wait for the spores to die off.

__________________
Just starting:

10 Gallon
1 Honey gourami
3 Peppered corys
3 Ghost shrimp

Wisteria
Aponogeton
Amazon swords
Anubias nana
Marimo moss ball
rotala indica

I would guess there is more than one problem going on here. Were the bulbs rotted when you took them out? It's normal for left over food to rot and get fuzzy by the next day. If there is food left over you are probably feeding too much. Rotting plants and left over food will cause an ammonia spike which will weaken fish making them prone to infection. It does sound like a fungal infection but it doesn't mean that it's the same problem the plants. While not impossible I've never known fungus to spread directly from plants to fish.

Also was the tank cycled? A planted tank doesn't always need to be but the plants might not be enough to stop it going through a normal cycle, during which time ammonia and nitrite spikes are normal. Do you have a test kit?

I'm not too sure about the API Leaf Zone plant food but it may be adding to the problem as some plant foods are rich in nutrients. Plants can only take in so many nutrients and in a new tank there may already be enough for your plants. Personally I'd stop adding it for a while or at least reduce the dose.

As for your PH leave it alone. Your fish will be fine with the PH you have. Most PH products cause much more harm than good, such as wild PH swings that are very stressful to fish. IMO they are only to be used by experts for a specific reason like getting fish to breed.

If you don't have one a test kit for ammonia, nitrites and nitrates would be useful. Other than that cut the amount of food you are feeding in half and don't add any more fish for about 3 weeks to give the tank a chance to finish cycling and get settled.