I don't know if they'll survive, I know they have to eat bacteria from other oto poop in order to get their digestive system going, but judging from the poop trail coming out of that one they might be alright. Besides that, this happened completely unexpectedly in my 42 gallon planted goldfish tank... with five large egg shaped goldfish. I'm not sure if the goldfish will end up eating them, and I can't really catch the oto fry because they are lightning fast... so then again, since the goldfish are such slow lumbering hulks, they probably won't be able to catch them and won't be much interested in them anyways. I have Ramshorn snails that lay eggs all the time and my goldfish don't like to eat them.
There are only about 5 otos in the tank, and I'm unsure of oto breeding habits. I'm guessing they are egg scatterers and the eggs must have fallen into the foliage of my plants. Or if they nested they certainly had the plants to do it in. I would estimate there are between 6-12 fry that I could see anyways. There's probably more.
My tank is very overcrowded... 5 goldfish, 5 otos, 2 dojo loaches, 3 Borneo suckers, 2 zebra plecos, 2 rubbernose plecos, 3 bushynosed plecos, 5 Siamese algae eaters, various snails, and 6 African dwarf frogs.
Plants include purple cambomba, anacharis, crypts, anubias, melon swords, valis, moneywort, and creeping jenny.
Tank specs however are 0 ammonia, 0 nitrite, and 0 nitrates.
Dissolved oxygen is 7.5-8
ppm, and phosphates are on the low end of the scale. Dissolved
CO2 is between 15-20
ppm. I change 15 gallons of water and replace with
RO/
DI water once a week. After which I dose various bacteria, including Microbe-Lift, Stability, and Acquamarine Phosphate and Nitrate bacteria. I also dose the Seachem Flourish line of plant supplements. I use Seachem buffers to treat
RO water for kH/pH and Kent Botanica to raise gH. (Seachem's Equilibrium has way too much potassium in it for my preferance.)
Here's my tank a couple of days ago:
I like equipment.
Here's underneath the tank on the left:
The canister is the Eheim 2128 Thermofilter. Water goes from the tank to that. An airline taps into the Eheim's output line and feeds small amounts of water to an Aqua-Medic Nitratreductor 400 (which is sitting next to the Eheim) through the yellow Vario dosing pump. This is an anaerobic bacterial Nitrate Filter. It is extremely efficient and is able to maintain 0 nitrates in even my tank.
The Eheim's output goes to an 18W Ultra Violet TurboTwist Sterilizer which is mounted next to the Vario pump.
Now here's the right side underneath:
The output from the TurboTwist feeds an Aqua-Medic
CO2 Reactor 1000 (which gets just a little over 3
CO2 bubbles per second). Since there is a lot of feeding and tubing involved, the water flow needs boosted. Above the Aqua-Medic
CO2 Reactor 1000, I have mounted a Maxi-Jet 1200 Powerhead. The water finally returns to the tank from below the
CO2 Reactor 1000.
Here's my controllers:
On top is an American Marine pH monitor. If pH falls below 6.9,
CO2 is shut off. So far this has never happened.
I recalibrate once a month and I hardly ever have to adjust it.
Underneath is the controller hooked up to a redox probe inside the Nitrate filter. In order for the anaerobic bacteria to effectively reduce Nitrate, the redox of the water must be negative, between -50 to -200. If it drops below -300, the bacteria will become septic and start to sulfate, producing hydrogen sulfide. It's not that dangerous though, because as soon as hydrogen sulfide hits oxygen rich water, it turns to sulfate which is relatively harmless. The controller turns the Vario dosing pump on when the redox falls below -200. If the redox rises above -200, the controller turns the Vario dosing pump off. This keeps the redox around -200 all the time. The Nitrate Filter has its own internal pump that keeps all the water inside circulating from top to bottom so no "dead spots" form.
Finally here's the tank thermostat hooked up to the Eheim canister:
In addition to all of the above, there is an Aquaclear 300
HOB filter on the back of the tank.
Additional filter media includes Seachem Purigen, and I also run a diatom filter once per week.