I started this project aiming to use only fish sounds; to really push myself creatively. So often I produce and am overwhelmed by the variety of instruments and samples to choose from. I felt that limiting myself to only the fish samples would be a great exercise in sample manipulation and would encourage me to explore the capabilities of plugins I own.
As I worked on the project, I ended up using a few drum sounds and other samples, however the bulk of the project remains fish sounds. I've colour coded the project within Logic for clarity:​​​​​​​

PINK = VOCALS, PURPLE = FISH SAMPLES, GREEN = FISCHER PRICE TOY SAMPLES, BLUE = OTHER SAMPLES (SPLICE)

The first element/instrument I started with was a bass sound. I find starting with a bass-line can provide a foundation for the rest of a track. ​​​​​​​

Midshipman fish hum

I used the hum of a midshipman fish for this bass sound. I tuned the hum using Melodyne and then imported it into Logic Pro's "Sampler" instrument. I intended on using this sound as a monophonic bass, but ended up liking the organ-like quality of the resulting instrument, so I played it polyphonically as an organ in a low octave. This polyphonic sound provided more tonal information and thus musical guidance moving forward, whilst still occupying low frequency ranges providing bass characteristics. 
As I create music I love to hum melodies and rhythms over the top of what I'm producing. For this piece I didn't want to have a vocal as the focus of what I was making; nor did I want to write lyrics for this piece, so I tracked the vocal ideas I was having as hums and cut the highs to 2200Hz. I then added Soundtoys "Little Plate" reverb to place this part both further back in the mix and give it an underwater feel:

Vocal hums (Processed)

Next, I constructed drum samples using fish sounds. The kick was made using a sound from an underwater sample. Originally a clean sounding sub "thump" I ran it through iZotope Trash 2, a distortion plugin, followed by an equaliser, cutting the high frequencies so that only the lows had been attenuated. Next, I parallel processed the kick sample using an instance of iZotope Trash 2, this time cutting the lows through an EQ to find a high end character I liked.
Sounds of water dripping was chopped to form a hi-hat pattern, which gave the track more movement. 
From here, I extended the song and began layering with more sounds, starting with some sounds added by fellow students into a Dropbox folder. The hi-hat was layered with the addition of the sound of tapping on an air-conditioner unit. More traditional snare sounds were added from Splice, a royalty free subscription based sample platform. Here's the full drum loop:​​​​​​​

Drum loop

Other percussive sounds in the project included Fischer-Price children's toys, after I searched my personal sample library for "fish". I didn't process these samples to a great extent- they were percussive and I didn't want to lose the rhythmic information by distorting or adding reverb (there is only reverb on one of the four Fischer-Price tracks). I mainly affected the stereo presence- using a sample delay, which separates the audio into two channels, left and right, and delays the signal on one, creating the Haas effect; a psychoacoustic phenomena that causes the audio to sound much wider without affecting the colour of the signal. Here's the full Fischer percussion loop:

Fischer-Price toy percussion loop

Tonal elements were then used to give the song more of an arc. I was able to search Splice for samples in F#maj, the key of the piece and then chopped the samples to fit into the context of the elements I had already included. I included flutes, synths and gospel choir samples at the end which brought the feeling of a conclusion to the piece. This is how these tonal elements sound both isolated and in context:

Tonal elements (ISOLATED)

Tonal elements (IN CONTEXT)

Now with a full structure and arc, I was ready to export the piece. I used Plugin Alliance's Masterdesk Classic with the following settings to slightly widen and colour the sound:​​​​​​​
This was then followed by Logic's stock limiter, which gave the resulting file an output level of -0.1dB; a level I have been taught is suitable for streaming.
Here's the full arrangement: