𝗙𝗜𝗦𝗛 𝗦𝗘𝗟𝗘𝗖𝗧𝗜𝗢𝗡: - Obsidian Aquatics


Fish selection! Where do I start?

Fish selection is arguably the most important part of your aquarium introduction journey. Pairing the right fish in the correct environment can not only look beautiful, but provide your pet with a long term environment they can thrive in and give you the satisfaction of providing that for them.

On the other hand, providing the wrong care and pairing the wrong fish together can cause undue stress, fighting, create problem areas in the tank and have adverse affects on the fish if they are from entirely different waters.

Every species of fish has their own water quality requirements. Forget what you may have heard, pH is NOT the only thing we test for!

A comprehensive list of things we test for include but are not limited to:

pH (hydrogen ions) - acid & alkaline.

Ammonia (NH3/NH4) - first stage of bacterial breakdown 

Nitrite (NO2) - second stage of bacterial breakdown

Nitrate (NO3) - final stage of breakdown, removed with water changes.

GH (general hardness) - calcium & magnesium ion's

KH (carbonate hardness) measure of carbonate/bi carbonate.

Phosphate (PO4) contains elemental phosphorous.

All of these things affect how our environment functions. as stated all fish require different parameters depending on where they are endemic to originally. Generally collective species of fish from the same regions will usually always require the same water parameters, with some exceptions. 

Here are some things to do if you are unsure:

-Research the particular fish you are looking to buy before purchasing and learn about their requirements and compatibility with other fish you like.

-Think about what you would like in your aquarium, whether you would like a planted tank, decorations, rocks and driftwood. Some fish will impact these systems in different ways. Especially if you are going for a high tech planted tank. Some fish can eat, tear up, blow holes and rip up those beautiful plants!

-Ask a professional: you can email us anytime with your inquiries if you are uncertain about any of the aquatic pals in our inventory. message us at info@obsidianaquatics.com.au or on any of our social media platforms and we will happily provide the answers you're searching for!

Beginner mistakes to avoid:

-Impatience. this is a BIG ONE! patience is one of the key parts of this hobby. Getting fish too early, rushing your decisions, not asking for help and not doing your research can all lead to disaster. Make sure you refer back to the list above if you are unsure of anything.

-Buying fish that will get TOO BIG (without a plan). We have all fallen victim to this before: "it wont get too big, it only grows to the size of its tank, right?" unfortunately the answer is NO! fish grow based on a combination of their genetics, personal feeding habits, ability to graze and the list goes on.... every species has a unique adult size and should be treated and planned for accordingly. if you are unsure about the max size of your fish. refer to the description of our inventory where we give all that information away!

a few common fish sizes to help you on your journey to avoiding mistakes:

-gold fish: fancy goldfish like oranda's, ranchu's, fantails and black moors, all range in size from 15-25cm at adult size. some of the bigger species such as comets, will grow 30-40cm. they are quick to grow and will usually get to 7cm in their first year.

-silver sharks/bala sharks:

silver sharks are found in parts of the Malay peninsula, Sumatra and Borneo. they are not actually a member of the shark family but rather a minnow. they grow to approximately 35-40cm (14-16 inches).

-black ghost knife: 

found in south america, these guys can grow to roughly 50cm (19.5 inches) in length. they are nocturnal and use electropulse to find insect larvae!


found in the warmer waters of south america, these guys pack a punch at 30-40cm fully grown. while most will remain closer to the lower side of the equation, they absolutely have the potential to get well over 30cm (12 inches)

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