I know these have been answered with correct information, but I'm going to give you my two cents worth as well.. from experience of keeping fish for the last 18 years, and from tons of research done from myself, and other keepers who have had these fish for decades:
Originally Posted by willm
[*]How likely are plastic plants to harm my betta's fins? I just added two fake plants to my tank to complement my two live ones.
Soft plastic ones should be fine- as long as they have no points or spikes- and are not the bushy ones with small points. Those are notorious fin rippers. Keep in mind their fins are like wet tissue paper.. even using a net on them will cause fins to split.
[*]I also just added two Otocinclus Catfish to my tank to keep my betta company. After doing some research I found that these make suitable tankmates for bettas. However, my betta has been chasing them a bit, and flaring at them. They're far too fast for him to cause them any harm, it seems, but I'm worried that all fish concerned might be stressed out by this show of aggression. My question is: how do I judge whether my betta is of the right disposition to share the tank with the two Otos? Is some chasing normal, or is it only safe if he completely ignores them?
In a 5 gallon you should not have any other fish in the tank for a number of reasons:
-The tank is too small to hold the bio load- the only reason you can get away with 2 bettas divided is because bettas don't give off a lot of ammonia due to them not using their gills as much, and they don't go to the bathroom as often as a lot of other fish such as goldfish. But if you put in other fish you are overloading the tank which can turn deadly easily and quickly.
-Ottos need larger groups and a larger tank- normally a 20 gallon for 4+ of them is recommended. They don't fare as well with only one or two.
-Ottos are hard to maintain, even for experienced keepers- even breeders have trouble time to time at keeping them alive. You have to supplement their foods and not just with wafers.. the tank must have a lot of live plants.
-Keeping multiple fish in such a small tank will cause them to feel "trapped", bettas are an aggressive species.. but individuals can vary to what degree of aggression they have. The natural instincts of territory of your betta is kicking in- such a small space he is wanting his territory without any other fish. He will continue to harass and chase until he can catch them. Those ottos are under a lot of stress and soon it will catch up to them in the way of illnesses and possible death due to being in a small place, with not enough numbers of them, and with an aggressive fish.
[*]When a betta becomes bloated from overfeeding, is it advisable to feed them a pea immediately, or to wait two days before trying the pea trick? I dropped an algae wafer to the bottom of the tank for the otos to eat, but my betta ate the whole thing instead. I left right after dropping it in there, assuming he wouldn't be interested, but came back to find the whole wafer gone and my betta visibly bloated.
Peas are meant for goldfish who are constipated. It is okay for a one time try on a betta... but very not recommended. Peas are nothing but empty calories and carbs for bettas. Bettas are insectivores/carnivores, and their GI tracts are not set up for such roughage. The domesticated betta gets it in their processed foods- wild bettas get roughage from the stomachs of their prey.
It's best to fast a fish for a few days before going to the PROPER channels of helping a bloated betta. Actual bloating will have more symptoms then just a rounded belly. A rounded belly just needs time to expel the food- not add more in that will do nothing for the betta. If it's true bloating, you will see difficulty swimming and tilting (similar to SBD, but not to the extreme). When that is the case you would use live/frozen daphnia (you can collect daphnia year round at your home) or can use Epsom Salt at 1 tsp per gallon, daily 100% water changes for 5-8 days. But firstly always fast for a few days before doing anything else. And don't use the pea...
[*]Lastly, I'm wondering about filtered water vs. tap water. Every day or so I need to add some water to my tank to compensate for evaporation (it's a Fluval Chi), and I've been filtering the water I add with a brita filter so that the hardness of my tank water doesn't build up over time. Is this ok?
Use tap water.. don't use filtered, don't use bottled, don't use distilled.. tap water with water conditioner is the healthiest and safest way to go- no harm will ever come to using tap water as long as you use water conditioner (which you need to use regardless of water source). Using anything else will require you to add chemicals into the tank to produce what your water is lacking- and then that could cause trouble with the chemistry and it's just a mess. There is no reason to not use tap water. There are some fish who are very sensitive to water chemistry, such as discus, and even then you would want to use tap. I know you are concerned and want to give your betta the best, but you are giving them a disservice by not using tap water.
Bettas aren't sensitive to hard water- they will adapt. Fluctuations in hardness can actually kill the betta though- you do not want to mess around with your natural hardness. Top off with tap water with water conditioner when needed.. it's not only healthier, but safer.
Always use tap water...
About the size of the tank-- I read about the "roughly 1 inch of fish per gallon" rule of thumb. I have about 3 inches of fish and 5 gallons, so I thought I'd be OK. Does this rule not apply to bettas?
That rule applies to NO fish. It's old, and one of those "myths" that survive the time. You have to look at the bio load of the fish relative to the size of the tank, the cycle, and live plants. Even if you add in more live plants- you still do not possess the appropriate room, nor correct otto numbers, to keep that tank healthy and the fish happy. You have tried to do research, but when doing so one must be very careful as there are a lot of myths going about, and people who "think they know what they are talking about because they had no troubles for a month by doing the wrong thing". You should research the species and their needs, and then research in places where there are a lot of knowledgeable people who have years of experience with them. You will always find things that are not ideal, and you will find personal opinions.. there are even some things on this forum in a sticky above that majority here disagree on.
If you decide to upgrade to a 20 gallon to keep your ottos and to get more (that is highly recommended), then to feed them you would want to drop in their food towards the back of the tank, while keeping your betta busy at the front with their food- you can also drop in the otto's food before/after turning on/off the light.
A bit of info on ottos:
They are usually more weak and stressed than most fish, and some usually die within the first couple weeks of home-bringing. It is extremely important to make the trip home as quick as possible, and acclimate them very slowly
to the new pH of your tank.
One important point to remember is that they need to be added to a mature set up
, they will not do well in newly set up tanks as they are very sensitive to any swings in water parameters and any sign of ammonia or nitrites in the water will lead to early mortalities. I'm talking of at least 6+ months the tank needs to be set up and cycled.
Avoid any fluctuations
in any water parameters. As well as the normal ammonia/nitrite, they seem particularly sensitive to PH and nitrate fluctuations.. which you are doing by using filtered water.
Keep dissolved oxygen levels up and have a relatively strong water current.. which you can't have in a small tank with a male betta.
Try and have brown algae (diatoms) present in the tank, particularly when the otos are introduced, it is a great food source for them and it is their favorite. Algae wafers are not suitable for the only food source.
As mentioned above, these fish are a social species and as such need to be kept in small groups, a tank as small as 15 gallons will allow enough space for these fish to thrive but if you are planning on adding these to a community tank then a larger aquarium will be required.
Always keep these fish well supplied with a high vegetable diet and plenty of algae to consume. You will h ave to supplement the vegetables, and would need a lot more live plants and a larger tank to get the appropriate and safe algae needed.
Those are just a few things you need to consider before keeping these fish.. It doesn't sound as if your tank is suited for them, even if it was larger.. unless you went through the appropriate cycle and it has been established for quite some time. I would highly consider bringing them back and keeping just your betta in the 5 gallon- if given more live plants such as java moss, you can pick up a few shrimps- but by the sounds of it, your betta is too aggressive for them as well. It's for the health and safety of your ottos to remove them and bring them back, also for the health of your betta as it sounds that having them in there with him is causing him a great deal of stress. Stress for fish is a big killer..