Algae and melting?

[Oblio]

Cories aren't algae eaters so they won't have much impact on it.

They seem to grazing on it. Perhaps* the Tetras are stealing their pellets and they are hungry?

* - Actually they do steal the pellets, but I try to ensure that several are missed by the little banditos.

 

[Essjay]

Cories are omnivores which need meat (fish/shrimp) based food with some veg matter. They could well be eating micro-organisms living on the algae. While they may eat some algae, they won't eat enough to eradicate it.

 

[Byron]

Corydoras will graze all surfaces they can get to, be it substrate, wood, rock, plant leaves. They do not eat algae or any vegetable matter, at least not intentionally; vegetable matter actually harms their digestive system. Technically, they are strictly carnivorous, eating insects, insect larvae, worms, crustaceans. They do not have teeth, so this food must be small. You would be amazed at the amount of microscopic critters that can live in the biofilm, and this is what the cories are hunting. And why they dig into the substrate and take up mouthfuls of sand, expelling the sand via the gills and swallowing any bits of food.

Unless you overfeed them, cories will continually be grazing/browsing surfaces, except when they decide to "chill out" and rest. Bug Bites are the ideal prepared/dried food for cories. Frozen daphnia, shrimp and minimal worms are good--go easy on the worms, once a week is enough.

 

[Oblio]

Thanks for the info and recommendations @Byron . Everyone seems to be loving dried tubiflex worms, it's a shame that it can only be a weekly treat. They are like freshman at a frat party with endless PBR on tap, you can almost make out the Red Solo Cups.

 

[DoubleDutch]

This also popped up about the time I reduced the light. I don’t necessarily mind it, as long as it doesn’t spread.

Added: On closer inspection it seems the bumps on the algae are bubbles, CO2 perhaps?

These are cyano bacteria.

I hardly dare to say the word : nitrates ?

 

[Oblio]

These are cyano bacteria.

I hardly dare to say the word : nitrates ?

After a 50% WC 2 days ago, the nitrates are <5 ppm, the growth was prior to to the change. I also noticed some green on a small portion of the substrate. I also just started to add some Pothos terrestrial plants to the tank to help with the nitrate.

 

[Byron]

Thanks for the info and recommendations @Byron . Everyone seems to be loving dried tubiflex worms, it's a shame that it can only be a weekly treat. They are like freshman at a frat party with endless PBR on tap, you can almost make out the Red Solo Cups.

If the "dried tubifex worms" are freeze-dried, don't feed them. Frozen (fresh frozen) bloodworms are OK but only once a week. Same for live worms. The nutritional make-up of worms especially the "popular" bloodworms is not exactly good for cories (or other fish either).

 

[Byron]

After a 50% WC 2 days ago, the nitrates are <5 ppm, the growth was prior to to the change. I also noticed some green on a small portion of the substrate. I also just started to add some Pothos terrestrial plants to the tank to help with the nitrate.

I went back in this thread, and I agree with @DoubleDutch that the green in the photo does look like cyanobacteria. This is caused by excess organics in the presence of light. Nitrates is often (but not always) an indicator of organic matter. The white dots are not bubbles; not sure what they are, but I would suspect bits of solid organic matter that sometimes appears in aquaria.

Nitrate occurring within the biological system of the tank (as opposed to being present in the source water) can be dealt with by water changes, substrate vacuuming during the W/C, keeping the brown gunk out of the filter, not overstocking, not overfeeding, and fast-growing aquatic plants, especially floaters.

 

[DoubleDutch]

I went back in this thread, and I agree with @DoubleDutch that the green in the photo does look like cyanobacteria. This is caused by excess organics in the presence of light. Nitrates is often (but not always) an indicator of organic matter. The white dots are not bubbles; not sure what they are, but I would suspect bits of solid organic matter that sometimes appears in aquaria.

Nitrate occurring within the biological system of the tank (as opposed to being present in the source water) can be dealt with by water changes, substrate vacuuming during the W/C, keeping the brown gunk out of the filter, not overstocking, not overfeeding, and fast-growing aquatic plants, especially floaters.

What I meand is that plants need a nitrogynsource. IMO is that nitrates, in others ammonia / ammonium

 

[Oblio]

The camera did not focus well on the bubbles. I just gently brushed them with hair fine artificial grass plant any they rushed to the surface as a tiny dot and then vanished.

 

[Oblio]

More on the bubbles, Cory's comment seems spot on to what I noticed re: BG 'algae'

 

[Byron]

More on the bubbles, Cory's comment seems spot on to what I noticed re: BG 'algae'

This is all very nice, but...the photo back in post #14 does not in my view show bubbles; for one thing, they are white not clear, for another they are different shapes with some long or rectangular, and these are not bubbles.

One has to take advice from people like Cory with the proverbial grain of salt. He is recommending antibiotics as the best treatment for cyanobacteria, and that is not at all intelligent. You deal with "problems" by solving the cause, not dumping chemicals and dangerous antibiotics into the tank.

[edited to correct spellings]

 

[Oblio]

The camera had trouble focusing on the bubbles. I agree with you re: adding antibiotics vs. treating the cause. Hopefully, the reduction in light intensity & duration, along with a more aggressive nitrate reduction (larger WC %, substrate cleaning, plants) will solve the problem.