Gyarados problems :/..

It's up to you, but twister sucks. I wouldn't power up any of them. It's a waste of candy/dust.

Gyarados with hyperbeam? You mean Dragon pulse or hydro pump?

In my opinion, the cp is too low, if it was cp 1700+ or so, I would do it. And also the IV isn't great.

So if I were you, I would save dust. You'll need it ;)

twister is not bad in gym defending at all,
depends on the way u play this game,
if u prefer attacking gyms, go for the hydro pump one,
if u prefer defending gyms, then power up the twister

Twister is terrible for attacking and defending, don't put stardust into them.

Twister isn't terrible on defense. Gyarados is though. I love seeing them so I can finally use electric type. It makes them a joke and everyone has a jolteon at least.

It's just a cool trophy Pokemon if you can't use it on offense. Mine also has twister, so I'm not hating on you.

Gyarados is only terrible at defending gyms if it has Twister. Twister is really bad.

Other moves on Gyarados aren't bad.

A low level Gyarados is easy prey for an electric, but if Gyarados is higher in the gym ranks then it will be silly for an attacker to be using an electric, as switching creatures causes a lot of damage to the attacker as you miss dodges and what not in the process of changing creatures.

So if you intend to power up your Gyarados to 2300 CP or higher than Gyarados can be a decent defender as long as it doesn't have Twister.

You've already answered your question, since you said magikarp is an easy pokemon to capture around your city... I don't think its worth, you can get others which can start at least around 900 CP with good movesets... and if you're target is to put them into a hight position at the gyms, it'll be fast if you do it with some pokemon with an already high CP

You've already answered your question, since you said magikarp is an easy pokemon to capture around your city... I don't think its worth, you can get others which can start at least around 900 CP with good movesets... and if you're target is to put them into a hight position at the gyms, it'll be fast if you do it with some pokemon with an already high CP

its not only the double weakness that makes Gyrados far behind the defender tier list,
its Bite and Dragon Breath, that makes it so ineffective in defending gyms,
without STAB, and consider the defense of the attacker, those attacks are really useless
if you choose Dragon Pulse and Hydro Pump, AI will be doing Bite most of the time in battle, which gives the attacker almost damage free
and here is the true value of Twister, in which it will doing much less Bite, and spamming Twister all the time
will you beg your luck on Hydro Pump and Dragon Pulse, or rely on spamming Twister?