How much algae do I need for Otos?

jaybrew

Hi, I'm a new aquarium keeper and I've been taking the slow route getting things set up. I have a 75 gallon tank which I did a dry start on to get a nice carpet of sag and dwarf hair grass going. It now covers most of the bottom of the tank. I've planted a variety of other background and midground plant, but they are still just getting going. I also have some floating plants whirling around in the current. I have some manzanita driftwood and a few rocks to weigh things down. The tank has been flooded and running with Oase canister filter for about a month. I've done a couple of big water changes and the ammonia, nitrites, nitrates and phosphorus parameters are perfect. My water is very soft though and I'm going to add some crushed coral to a filter tray to get the kH and gH up. I'm also currently experience a bloom of floating algae, but I have a UV clarifier on it's way from amazon. There doesn't seem to be much algae on the surfaces. The glass is very clear as is most of the wood. There is what might be brown algae growing on some of the wood, but I think is actually mold/fungus from the new driftwood piece.
Once I get my water hardness up and the floating algae cleared I'd like to add my first fish. I really love Otos so I was wanting to add a nice sized school of maybe 10-12 as my first fish.
So, my question is: How much algae do I need in a tank this size for that many fish? I can crank up the light intensity and length, but I don't want to go crazy. Any advice is much appeciated. I'll add a pic of my tank as well as the stuff growing on the wood that may be brown algae or may be fungus. -thanks!

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MacZ

I would wait at least 4-6 months before adding Otocinclus. As specialized aufwuchs eaters (algae/biofilms/infusoria growth on surfaces), they need firmly established and sustaining aufwuchs in the tank, otherwise supplement feeding is necessary which has negative impact on water quality.

My water is very soft though and I'm going to add some crushed coral to a filter tray to get the kH and gH up.
What are the actual readings of GH and KH and what fish besides the Otocinclus do you plan to add? Maybe you don't have to change anything.
I'm also currently experience a bloom of floating algae, but I have a UV clarifier on it's way from amazon.
Wait it out. The tank is not running for long and it takes time to balance out.
There is what might be brown algae growing on some of the wood, but I think is actually mold/fungus from the new driftwood piece.
It's biofilm and some hair algae. Nothing unusual in this phase. Many algae will come and go by themselves within the first year of a tank. Don't do anything unless unsavory things like cyanobacteria show up. In which case light has to be dialed down.

So, my question is: How much algae do I need in a tank this size for that many fish? I can crank up the light intensity and length, but I don't want to go crazy. Any advice is much appeciated. I'll add a pic of my tank as well as the stuff growing on the wood that may be brown algae or may be fungus. -thanks!
As said above: I takes time. You want sustainable growth, not quick growth. Also you will want more driftwood, botanicals and leaf litter, because all this grows aufwuchs and as grazers these fish need a lot of surfaces to graze on, as they CONSTANTLY eat.
 

TClare

Good advice above. And just a small tip. To stop the floating plants swirling around you can make a corral for them out of airline tubing fixed to the tank sides with suction cups. It won't be needed as they become more established but helps to keep them place at first.

I was also wondering why you need to raise the hardness of your water? I have very soft water and all is fine, certainly fine for otos, but it does depend what other fish you want to keep.
 

86 ssinit

Yes the hardness is my question too. And welcome to fishlore! Is this your first tank? Next a dozen ottos won’t survive in that tank. Probably 4 will be more than enough. Thing is these fish only eat bio-film and certain algaes. A 75g just can’t produce enough for 12 to survive. Next as stated you need a well established tank of at least 4-6months for them and shrimp.

Tanks growing nicely but have you tested your water? The bloom should clear up without the steralizer. Just some filter floss added to the filter will help it along. Uv though is great for the tank.
 

jaybrew

Thanks everyone for the quick responses. I want to raise the kH because I've read that it acts as a buffer and stabilizer for pH. Here are my current readings:
ammonia: 0
nitrite: 0
nitrate: slightly above zero, maybe 10ppi
phosphate: didn't write down the result, but very low
calcium: I have a test coming in the mail so haven't done it yet.
pH: 6.8-7
kH: 2 degrees
gH: 3-4 degrees

I'm not sure if I'm reading the gH correctly, (API test, how green is green!?, haha, it barely looks orange at one drop). I'm taking a sample to my local aquarium store to have them test and see if it confirms my own results. So the gH may not be super low, but it isn't between 4 and 8 which I've read is good for most fish.

I'm planning on adding mostly small types of schooling fish like the smaller tetras, rasboras and corys. Also a few smaller loaches and rainbows. I might eventually put in an angel or two, but I'm concerned about size and aggression. Mostly I just want slightly larger schools of very small fish. Once the plants grow in it'll be a pretty heavily planted tank and I want to keep the bio load low. You can't see it well in the photo but there is a lot planted in the back, plus I just mowed down a bunch of eleocharis vivipara which I wish I had never planted. It's so messy and grows way too fast. I can already tell its going to be a hassle to control or get rid of.

I'll hold off on getting Otos until things are more established. I was hoping I could keep a larger school of them as they are one of my favorites, but ah well a smaller group will be okay. Black Emperor or Rummy Nose Tetras it is then!
 

MacZ

I'll hold off on getting Otos until things are more established
Good.
I was hoping I could keep a larger school of them as they are one of my favorites, but ah well a smaller group will be okay.
I think 8 should work if you triple the amounts of wood and branches and establish an area of leaf litter and wait a good 6 months. Then I see no problem why it shouldn't work if you prepare carefully and with the fishes needs in mind.
API test, how green is green!?
The moment it really turns is what counts. With a KH of 2 (confirmed?) the GH is very unlikely to be above 4-6 as they are usually in a certain ratio to each other (usually). But also with that KH of 2, the pH tests are off by up to +/- 1 whole point. I would estimate it rather towards 6.5, maybe 6.2.
Excellent conditions for amazonian fish, if the readings hold correct.

calcium: I have a test coming in the mail so haven't done it yet.
Return it. GH is the measurement of Calcium and Magnesium. You don't have to measure them separately.

phosphate: didn't write down the result, but very low
FYI: Actually not relevant for fish, with few exceptions.

Some bad news, though: Rainbow fish are pretty much out with that hardness range. Same goes for Corydoras and loaches (Except maybe Kuhli...). They need access to the substrate (which should be sand due to physiological need to chew and sift it.) which is not possible, am I right?
 

TClare

My KH and GH are even lower. I usually get pH 6.8 but perhaps this is a wrong reading as well as the KH is so low. In any case the pH does not seem to fluctuate a lot despite the low KH. I keep a variety of Amazonian species, the water is good for them. I would choose suitable species and not worry about changing the pH. I have 7 otos in a well planted approx 150 gallon tank, and a few more in an approx 63 gallon tank that has some plants and a lot of wood and leaf litter. I never give them any additional feeding and the tanks could probably support more.
 

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