Is It OK To Only Feed A Bristlenose Pleco Vegetables?

I have been having alot of difficulties feeding my bristlenose pleco algae wafers and pleco tablets. He loves them, but over time the neon tetras in my tank seem to have developed a taste for them and now they will try to eat them as soon as I put them in the tank. The tetras will gather around the pleco and nibble the wafer, and he will get very agitated and charge at them. They will also nip the fins and tail of my pleco to try and get the food (I have actually seen them do this), and my pleco has torn fins.

This has only seemed to happen in the last month or so, I have kept the neon tetras and pleco together for nearly a year without any previous issues. I have even tried putting in a wafer several hours after the tank lights go out, and the neon tetras are resting in the opposite corner, but they still wake up and go for the wafer.

To solve the issue, I have started to feed my pleco courgette slices and spinach leaves instead as the other fish have no interest in these. There is also driftwood in the tank. However I am concerned that he might not be getting enough protein and nutrients. Can a bristlenose pleco survive on a diet of vegetables and driftwood, and if not, how can I ensure that he gets enough protein?

Hi @Vanadia and welcome to the forum. 

I have a couple of bristlenose plecs in different tanks, with various tetras and corydoras. All of my tetras will eat algae wafers, but I've not had any problems with fin-nipping.

I'm not sure if a plec can survive on veggies & driftwood in a tank, though I guess they don't get any wafers in the wild.

There are a few things that you could try.
I have grown algae just by putting the rocks in some old tank water in a container on a sunny windowsill. A small pinch of fish food will provide nutrients. It takes a while to get a good growth, but my BN's love them.
You could also try leaving the tank lights on for longer, to encourage algae in your tank, but that can be quite a controversial approach, depending on how pristine you like the tank to look.
I'd also think that a variety of vegetables would provide a broader range of nutrients. My BN's and other algae eaters have eaten courgette, cucumber, carrot, and baby sweetcorn. There is a huge list of things these fish will eat, though some might be a bit trial and error to find things that they like. Others on this forum have used sweet potato, sweet peppers, and apple. If you have a search on the internet you'll find lots of different things that are considered suitable.
The other thing that I do is push algae wafers into softer veggies like cucumber and courgette. My tetras will nibble on these, but it keeps enough of the wafer "hidden" so it might provide your plec with more of a chance to get some.
Does your BN have a favourite cave of hiding place? My Bertie does, and I tend to put some cucumber with wafers in right in front of that. If you can do something similar it might reduce the access for the tetras, and again give your BN chance to eat undisturbed.

I hope that this gives you some ideas. 

According to websites that give the diet, bristlenoses need a varied diet, not just algae wafers. The suggestions include sinking dried food (which could be algae wafers or a meat based pellet), daphnia, mosquito larvae, bloodworm, prawn/shrimp (that's the kind we eat, cut into tiny bits), together with fruits and parboiled potato.
I have also seen it suggested to make your own food containing spirulina, mixed veg and meatier ingredients bound together with gelatin. Presumably these would need to be frozen to stop them going off.

Helen's experience shows that bristlenoses do indeed need some 'meat' in their diet as these other sites suggest.

There is this one as well, which is good for plecos
https://www.amazon.co.uk/Repashy-Fishfood-Morning-Wood-84g/dp/B00GMMWRLA/ref=sr_1_10?ie=UTF8&qid=1552851198&sr=8-10&keywords=Repashy
I've used both, "paint" them onto rocks and wood, then leave them to cool before putting them in the tank. The tetras will still pick at this food, but my BNs and bulldog plecs enjoy it. It also gets approval from my hillstream loaches, garras, gobies, and shrimp.

That's great news. 

I'm glad that your pleco is enjoying the Repashy food, and that your other fish have lost interest.