Did Ottos attack my Betta?

4 days ago I added two new ottos to my 10 gallon divided community tank (1 betta in smaller divided section) another betta In bigger community section with 1 original otto and 1 baby BN pleco).

I did daily water changes as soon as I added them 3 days in a row. I normally do them weekly. I just set up the 10 gallon a couple weeks ago but used filter/media, sand and driftwood from cycled 5 gallon and used seachem stability. It should be cycled.

The same afternoon, my community betta was missing some finage. The next day the tips of his fins progressively turned white and fell off. I was doing 30% water changes daily since I added the ottos.

Yesterday the community betta turned from pink to grey and was acting frightened- darting away and hiding from me (normally loves me). I noticed was covered in dark brown/red dots. These may have been scabs???? I immediately put him in a Tupperware with bettafix and he darkened back to his original colors within the hour, and returned to his normal personality. He still has one big red dot. I am doing 100% changes daily in the Tupperware and adding betta fix until his fins heal up. The Tupperware is floating in the 10 gallon to keep it warm.

I can only think that the 2 new ottos were starved at the petstore, and could think of nothing else to eat but my poor betta, before I even had a chance to give them real food (algea wafer). I have heard that a starving common pleco will go after a fish's slimecoat. Would ottos do that? Could it have been my new BN pleco that attacked the betta? Or was the betta just stressed by the 2 new tankmates?

This is really a question about the personality of ottos. I'm sorry that I rambled too much about my betta *shrug*

 

Welcome to Fishlore

I highly doubt otos were responsible for your betta's condition, however, it sounds like your betta is definitely stressed from having those other fish in with him in such a cramped space. Further, otos need to be in a group of at least 6 in a 20 gallon and the pleco should be in a 30 gallon minimum.

I would return those otos and pleco as soon as possible so you can get your betta out of that container. And then you can divide the 10 gallon evenly for both your bettas. I think they would be much happier that way.

Also, you say that the tank "should be cycled" but do you have a test kit to verify your water parameters? Fin damage can also be attributed to poor water conditions so if you don't have a test kit, I highly suggest buying one. The API Freshwater Master Test Kit is the one most recommended. I suggest daily water changes for now to help him heal.

Could you also attach a pic of the betta? I'm not sure what the red spot is or what it means.

 

In a different scenario, is 10 gallons undivide really too small for a school of 6 ottos? Fishlore states their bioload is negligible. If the space is used well with lots of plants and hiding, I seem think the amount of space could also be ok.

Also, why is a school always of 6? Is that really such a huge difference from 5? I get that if people said 5 is a group then some one would just put 4 in, then the next would go with 3... But is 6 really a magic number?

Also I read that a betta and a bristlenose would be ok in 10 gallons, since BNs only grow 4-5 inches. I get that adding another kind of fish is overstocking. The pet store said the otto would be fine alone and my intial quick internet search said NOTHING about them being in shoals. I learned that here.

Here's a link to photobucket where I put several photos. photos
Theres's one how he's supposed to be, one the spots, another of his discoloration, and one of him being in the tupperware. Also one of my tank, if any of that is useful.

The new ottos were very pale and skinny and the petstore. I don't think they had food. The red dots could be otto teeth marks, and the betta shied from movement and was hiding (perhaps like he was being chased...by...ottos) That's why I thought they could have tried to eat my betta's slime coat or something.

 

In a different scenario, is 10 gallons undivide really too small for a school of 6 ottos? Fishlore states their bioload is negligible. If the space is used well with lots of plants and hiding, I seem think the amount of space could also be ok.

Also, why is a school always of 6? Is that really such a huge difference from 5? I get that if people said 5 is a group then some one would just put 4 in, then the next would go with 3... But is 6 really a magic number?

Also I read that a betta and a bristlenose would be ok in 10 gallons, since BNs only grow 4-5 inches. I get that adding another kind of fish is overstocking. The pet store said the otto would be fine alone and my intial quick internet search said NOTHING about them being in shoals. I learned that here.

It's not just about bioload but activity level. A shoal/school is always much much larger in the wild. Of course, we can't have that many in our home aquariums but we still want to put them in as large numbers as possible to make them feel secure. Having just a couple isn't going to make them happy.

A BN Pleco even alone is not suitable for a 10g. A 5 inch fish does not belong in that small of a tank. You also have to consider that they are huge waste producers and it will be difficult to maintain stable water parameters in that size. Further, you're not even giving it the entire 10g... it's limited to a divided 5 gallon along with otos and a betta.

Otos are generally very peaceful and not known to bite or try to eat fish. But I do know that when they get to the store, they are usually starved and are usually best kept in established tanks. Since your tank is new, there may not be enough algae for them.

I still highly recommend that you return the fish mentioned. I doubt your betta is going to improve from whatever is ailing it under those conditions and it seems it's already very stressed by its new tankmates.

 

As far a my tank setup, when I do return the pleco and ottos, what would make an appropriate tank mate(s) for my betta? I've only had poor experiences with bettas+shrimp and I am tired snails. I'm mainly "fishing" for some sort of bottom dweller. I know that this betta will do well with the right tank mates. I just have to find them.

Would a school of 6ish dwarf cories be better? I'm fond of those and my lfs carries them. I could easily enough take out the divider and move the 2nd betta to another tank for that. I would also add more plants cover. Is there a different recommendation (maybe one where 2/3rd's of the tank is enough?

 

Bettas really don't make good community fish so I wouldn't advise another fish with them. Shrimp and snails would be the only other tank mates possible.

Dwarf corys need a 15 gallon minimum.

 

Every betta is different..there are many cases where bettas do not act in a way that textbook answers believe they should. In fact I was just reading a thread about it. Many people have success keeping a betta happily with fish like guppies. Some people find it harsh to condemn a fish to live in solitary confinement just because they are same-species aggressive.

Granted just because my betta is not aggressive towards other fish doesn't mean he likes them. I really would like to try to find the right community for him, but if he simply doesn't accept it I will of course respect his comfort zone.

As far a the newness of my tank: I know that most of the bacteria are on the filter of a cycled tank. Transferring the whole filter to the new tank and letting it run will also bring along a good chunk of bacteria. The seachem stability also ads some BB back into the water, which will help re-establish the BB that died in transfer. I have jump-start cycled a couple tanks using the old filter cartridges of fully cycled tanks. For this reason, I would not call this tank "new," even though it's not as established as a years old tank. I don't think there's any fin rot happening either- I think he ripped it or it was nipped and was flaking off from stress. The divided betta has no signs of rot. If the water were bad, wouldn't he have it?

The ottos definitely gained a healthier color and fattened up during the few days they'be been in my tank. I think they'll be ok for a couple more days until I can rehome them. The pleco should be fine for that time also- he is smaller than the betta so has plenty of space for now. The betta needs a couple days in betta fix, so no one in the 10 gallon will be bothering him.

 

But your betta that's in with other fish is clearly not ok and it doesn't have to be about him being the aggressor. He may appear fine for a few months but one day decide he's had enough and just snap. Large percentage of the stories we hear are ones where bettas with other fish don't work. I think the fin rot and whatever else that's ailing him is going to be progressively worse the longer he is forced to be in that space with other fish. I'm only saying these things for the well being of all your fish.

I still suggest you go out and get a testing kit to ensure your water parameters indicate you are cycled. Daily water changes are going to be the best thing for your betta right now as well as for your other fish. At the very least, I suggest getting your water tested at a store that uses liquid tests. A cycled tank should have 0 ammonia, 0 nitrite and nitrates that should stay under 40ppm, ideally under 20ppm.

 

Putting aside the debate on whether bettas could or should be in communities or not, the fact of the matter is that the 10 gallon tank is still divided. Any tank smaller than 10 gallons (which the OPs is with being divided) really isn't suitable space-wise for any fish except a betta (inverts not included). I'd debate even putting a betta in anything smaller than a 10.

If you'd like other fish I would strongly suggest looking into getting a larger tank (20 gallon minimum). This will allow for more options for stocking.

At the very least, please divide your 10 gallon in half so each betta has equal amounts of space. I'm sure your other betta would be happy to have a little more swimming space.

We need to keep in mind that just because X amount of fish can fit in a tank without overloading the BB, doesn't mean that we should. Swimming space is just as important as bioload.

 

Back to the ottos- would a lack of space make them uncomfortable enough to latch onto a curious betta? I don't know, I'm just trying to figure out how it happened so suddenly after they were introduced.

 

Back to the ottos- would a lack of space make them uncomfortable enough to latch onto a curious betta? I don't know, I'm just trying to figure out how it happened so suddenly after they were introduced.

Yes lack of space could of been part of the issue. If fish become aggressive towards each other in an aquarium they can't just swim away unless their is enough room to do so as well as many hiding spots.

It's why betta communities aren't recommended in anything smaller then a twenty gallon that is heavily planted. Meaning you can barely see the substrate and background.

 

I just read this page regarding how ottos arrive at pet stores. This page really ads form to my theory that the ottos were starving at the pet store and tried to eat my betta's slime coat before I had a chance to feed them. It would explain the sudden scabs on him and the sudden stress. Probably I should have fremoved the betta while they got used to the 10 gallon.

I won't be taking them back to the horrible place where they will probably die from starvation. I'm thinking about converting my 15 gallon to warm water when I upgrade my baby goldies anyway. Until then, I'll put the divided betta into a 3 gallon and let the ottos and community betta have the 10 gallon. The betta is totally fine now- even the ripped fins have quickly rounded off to a normal shape (and I suspect will regain their length soon.)

My 10 gallon has got several sizeable java ferns and java moss, also floating anubias. IT has a sandstone cave and a good chunk of driftwood. I've been trying to buy more plants for my tanks since I got my first tank, and it's hard to find enough to get that wild look. I will start by consolidating all my plants in for the ottos until I get/grow more.

The pleco is searching for a new home. Again, I can't take him back to the pet store or a novice like me will try to do the same thing to him. I'll screen people and find a knowledgeable home.

I'm really trying my best. Every beginner makes a stocking mistake- and when do we stop being beginners to the fish tank hobby? When the world runs out of new kinds of fish to keep.