Timing between health issues and new fish

[Familyfishny]

We just fought off ich in our tank, and resolved the problem that caused it (undersized gravel cleaner). We need to stabilize the tank for a couple of weeks and make sure everyone is okay and the tank parameters are normal. How long after that should we wait to replace our BN pleco and get the bronze cory group up to the recommended 5? Our tank furniture is getting pretty green .

 

[GaryE]

The gravel cleaner isn't at fault. Ich is a parasite that travels, and if it gets in, any tank will be attacked. If you have killed it off, you'll know in about 3 weeks after treatment. If it's been killed, it won't be back until another set of fish carry it in. It needs hosts to feed on to survive.
Since it's like any parasite and picks on the weak, stressed and crowded, it is something to watch for when purchasing those new fish.

I've treated Ich and had it not revisit for 10 years. And I've had it show up three times in a year. It's why a quarantine tank is suggested, although few people have them.

 

[Alice B]

I have a shed full of quarantine tanks but I used to have 13 aquariums too, some overkill is not necessarily a bad thing. I'd wait at least a month at normal temps before adding fish to this tank, and I would set up a quarantine tank with a filter and bottled bacteria (fritz or biospira) and start keeping the new fish in it. good heater too

 

[Byron]

On a couple other observations, you need some floating plants. The green algae on the rock is natural and in my view attractive, but with no floaters overhead this is inevitably going to spread and attack the plants, something you do not want happening. Aside from algae, floating plants provide as natural habitat for the fish as most of them are forest fish and overhead light is anything but normal or harmless.

And on the cories, you need more than five. Tank size is not stated, but it is sufficient to have a group of 9-10 and that will make a huge difference in fish health--including keeping ich away. Stress causes over 90% of aquarium fish disease/health problems, and cories are social shoaling fish. A group of around 10 makes a big difference over five or six, scientific studies have proven this. And, add them together at the same time, something applicable to all shoaling species. This too helps avoid ich, as the stress is lessened by having all of them together.

 

[Familyfishny]

Thanks, folks. The tank is 37 gal, and we currently have 8 guppies and 3 cories. Could it hold more cories and an adult pleco? That seems like a lot.

 

[Alice B]

What is the footprint of the tank? the air exchange allowed by the foot print is really the limiting factor in tank size / health. I have a 38 gallon hex and I can't stock it like I can my 29 because it is tall and narrow

 

[Familyfishny]

Rectangular and tall; relatively standard, but maybe a bit taller and narrower than some. It has a hang-inside waterfall filter that I could upgrade if you think it would help, and a bubble wall. I like the idea of floating plants, the light is pretty relentless. The submersed plants are already not happy, but I could start the floating plants on the opposite side.

 

[Alice B]

the corydoras would definitely like some floating plants, maybe some frogbit. I will let Byron suggest how many corydoras, he is more of an expert on them and you have had the disease issues as well, and you want to be sure you are past them. I always recommend a quarantine tank. Always a good investment

 

[Familyfishny]

I agree! I have a little 3 gal, but euthanized a guppy in it last month and haven’t figured out how to get the clove goop off the bottom. But hey, I have at least a month to figure it out . Should I quarantine incoming floating plants as well?

 

[Byron]

Corydoras here will be OK with 10-12, I would consider 15 if it were me. There is no doubt at all but that cories will be in better shape (= healthier) the more there are, so rather than looking at more as being a negative it is in fact a positive, as they will have less effect on the biological system with more. Less stress too.

The pleco if it is a Bristlenose should be OK. However, I do not see any wood in the tank, so do not get a BN. They must have real wood to graze; they do not "eat" it as nutrition but it keeps their intestinal tract healthy due to some bacteria thing.

On another issue, water parameters--these are not given, but if you are in New York city you have soft to very soft water. The guppies may struggle, I personally would not get more livebearers as they need harder water. The cories will thrive, as will the BN and most any soft water species. With the 12-15 cories, BN and existing guppies, there is plenty of space for other small fish, most of which will be shoaling so that means groups of 10-12 minimum per species. We can advise on suitability if you have some in mind. I don't see any problems provided you get some floating plants. You could reconfigure the filter if needed to provide good but not excessive surface disturbance.