happychem said:
Personally, I strongly disagree with the notion that short periods of direct sunlight causes algae, yet one often finds mention of this on the web. It's a rediculous notion that doesn't stand up to anything I've ever observed. My 33 gal gets about 3 hours of direct sunlight on one side during the summer, that side doesn't have any more algae than the rest of the tank. Now if your tank was getting a full day of direct light, perhaps it could be an issue, but I think that a vast minority of tanks fit this profile.
I do have very little gas exchange compared to most people. Meaning that my tank is filtered, but I have plants situated to cut down on a lot of the surface agitation. Here's a picture of the tank in question:
Get your NO3 and PO4 levels tested, this will help identify the cause of the algae. If this is a relatively new tank, don't stress, I've pretty much always had a little algal bloom in new tanks, unless I started with CO2. With attention to maintenance and a little diligent cleaning the period of the algae is quite short.
I have the kit to test those and was going to do it tonight. But when I sat down at the computer after waterchanging my 36g tank, I noticed two of the otos in the betta tank (the one we are talking about here) were acting very bizarrely.
They are chasing each other up and down the glass and in circles on the glass. Always on the glass. Actually, the bigger one is chasing the smaller one and I'm going to have to assume that the big one is male and smaller one is female. I don't know how to tell them apart.
They're both doing fly-bys -- almost a dance. I went to the otocinclus site and I'm positive they are spawning. Kid you not!
They've been at it for at least an hour now and I don't know when they started this.
Interesting thing of note: the betta fish seems to be purposely staying out of their way. He's letting them have the entire run of the front part of the tank and he's just watching them. Once in a while he comes forward and follows one, but it doesn't look agressive; more like curiousity.
At one point the male (I think) flipped out. Went coursing around the tank and settled on the back wall. I think he was exhausted. He stayed there for about 10 mins and then went back to the female. Their circles are smaller now and there's more fly-bys. She stops for a few seconds now and then to eat off the glass, then she's off and circling. She's not really stopped at all. He is *definitely* chasing the smaller one.
I did see the female go to the pipstone and clear a little off, but the male didn't go there. I doubt she deposited anything. She keeps stopping at the same part of the glass and eating. I think she's clearing some of the glass off.
Dammit! I have to get to bed and can't stay and watch this. I want to know if I'm right and they are spawning. This is SO exciting!
I wouldn't add any more Otos to that tank, you could probably add one or two more, but they'll be happier as they are. Just add some more plants if it's your planting is sparse and they'll be fine. As long as they have places to hide they'll do okay. The betta should stop chasing them after he gets accustomed to their presence. Worst case he'll take a nip at the dorsal fin and get a dose of an Oto sting, he'll pretty much leave them alone after that.
I don't even see the 3rd one. He could be hiding with all this activity going on or dead. I don't want to disturb the cople at all. I'm not even going to turn the light off like I usually do before bed.
I'll update in the morning. Maybe they'll still be at it.
I could be out to lunch, but my instincts tell me no.
Roan
